diff --git a/package.json b/package.json
index 58a655f..76fd2bf 100644
--- a/package.json
+++ b/package.json
@@ -22,21 +22,23 @@
         "type": "git"
     },
     "scripts": {
-    "test": "NODE_PATH=src node node_modules/.bin/ava 'tests/*.spec.ts' -e",
-    "test:debug": "NODE_PATH=src node inspect node_modules/ava/profile.js",
-    "test:all": "NODE_PATH=src node node_modules/.bin/ava",
-    "lint": "tslint -p tsconfig.json",
-    "validate:tslint": "tslint-config-prettier-check ./tslint.json",
-    "prepublishOnly": "yarn lint && yarn test && yarn tsc"
+        "test": "NODE_PATH=src node node_modules/.bin/ava 'tests/*.spec.ts' -e",
+        "test:debug": "NODE_PATH=src node inspect node_modules/ava/profile.js",
+        "test:all": "NODE_PATH=src node node_modules/.bin/ava",
+        "lint": "tslint -p tsconfig.json",
+        "validate:tslint": "tslint-config-prettier-check ./tslint.json",
+        "prepublishOnly": "yarn lint && yarn test && yarn tsc"
     },
     "dependencies": {},
     "devDependencies": {
         "@types/chai": "^4.1.7",
         "@types/node": "^12.7.2",
+        "@types/sinon": "^7.0.13",
         "ava": "^1.0.0-rc.2",
         "chai": "^4.2.0",
         "mhysa": "./",
         "prettier": "^1.14.3",
+        "sinon": "^7.4.2",
         "ts-node": "^8.3.0",
         "tslint": "^5.11.0",
         "tslint-config-prettier": "^1.16.0",
diff --git a/src/functions/compose.ts b/src/functions/compose.ts
index da46ee8..00ff00e 100644
--- a/src/functions/compose.ts
+++ b/src/functions/compose.ts
@@ -29,6 +29,7 @@ enum EventSubscription {
     All,
     Self,
 }
+
 const eventsTarget = {
     close: EventSubscription.Last,
     data: EventSubscription.Last,
diff --git a/src/functions/demux.ts b/src/functions/demux.ts
index 138e6c7..9c9e624 100644
--- a/src/functions/demux.ts
+++ b/src/functions/demux.ts
@@ -1,5 +1,27 @@
 import { WritableOptions, Writable } from "stream";
 
+enum EventSubscription {
+    Last = 0,
+    First,
+    All,
+    Self,
+    Unhandled,
+}
+
+const eventsTarget = {
+    close: EventSubscription.Self,
+    data: EventSubscription.All,
+    drain: EventSubscription.Self,
+    end: EventSubscription.Self,
+    error: EventSubscription.Self,
+    finish: EventSubscription.Self,
+    pause: EventSubscription.Self,
+    pipe: EventSubscription.Unhandled,
+    readable: EventSubscription.Self,
+    resume: EventSubscription.Self,
+    unpipe: EventSubscription.Unhandled,
+};
+
 /**
  * Return a Duplex stream that is pushed data from multiple sources
  * @param streams Source streams to multiplex
@@ -76,4 +98,24 @@ class Demux extends Writable {
             });
         }
     }
+
+    public on(event: string, cb: any) {
+        switch (eventsTarget[event]) {
+            case EventSubscription.Self:
+                super.on(event, cb);
+                break;
+            case EventSubscription.All:
+                Object.keys(this.streamsByKey).forEach(key =>
+                    this.streamsByKey[key].stream.on(event, cb),
+                );
+                break;
+            case EventSubscription.Unhandled:
+                throw new Error(
+                    "Stream must be multiplexed before handling this event",
+                );
+            default:
+                super.on(event, cb);
+        }
+        return this;
+    }
 }
diff --git a/tests/compose.spec.ts b/tests/compose.spec.ts
index f05a248..6b97798 100644
--- a/tests/compose.spec.ts
+++ b/tests/compose.spec.ts
@@ -1,6 +1,6 @@
 const test = require("ava");
 const { expect } = require("chai");
-const { compose, composeDuplex, map, rate } = require("../src");
+const { compose, map } = require("../src");
 const { sleep } = require("../src/helpers");
 import { performance } from "perf_hooks";
 
@@ -308,12 +308,12 @@ test.cb(
     t => {
         t.plan(6);
         interface Chunk {
-            index: number;
-            mapped: string[];
+            key: string;
+            mapped: number[];
         }
         const first = map(
             async (chunk: Chunk) => {
-                chunk.mapped.push("first");
+                chunk.mapped.push(1);
                 return chunk;
             },
             {
@@ -324,9 +324,10 @@ test.cb(
         const second = map(
             async (chunk: Chunk) => {
                 pendingReads--;
-                await sleep(500);
+                await sleep(200);
+                expect(second._writableState.length).to.be.equal(1);
                 expect(first._readableState.length).to.equal(pendingReads);
-                chunk.mapped.push("second");
+                chunk.mapped.push(2);
                 return chunk;
             },
             { objectMode: true, highWaterMark: 1 },
@@ -342,27 +343,25 @@ test.cb(
 
         composed.on("drain", () => {
             expect(composed._writableState.length).to.be.equal(0);
-            expect(performance.now() - start).to.be.lessThan(100);
+            expect(performance.now() - start).to.be.lessThan(50);
             t.pass();
         });
 
         composed.on("data", (chunk: Chunk) => {
             // Since second is bottleneck, composed will write into first immediately. Buffer should be empty.
             expect(composed._writableState.length).to.be.equal(0);
-            expect(chunk.mapped.length).to.equal(2);
-            expect(chunk.mapped).to.deep.equal(["first", "second"]);
             t.pass();
-            if (chunk.index === 5) {
+            if (chunk.key === "e") {
                 t.end();
             }
         });
 
         const input = [
-            { index: 1, mapped: [] },
-            { index: 2, mapped: [] },
-            { index: 3, mapped: [] },
-            { index: 4, mapped: [] },
-            { index: 5, mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "b", mapped: [] },
+            { key: "c", mapped: [] },
+            { key: "d", mapped: [] },
+            { key: "e", mapped: [] },
         ];
         let pendingReads = input.length;
 
diff --git a/tests/demux.spec.ts b/tests/demux.spec.ts
index cdc91d5..9ff3498 100644
--- a/tests/demux.spec.ts
+++ b/tests/demux.spec.ts
@@ -1,53 +1,38 @@
 import test from "ava";
 import { expect } from "chai";
-import { demux, map } from "../src";
+const { demux, map } = require("../src");
 import { Writable } from "stream";
+const sinon = require("sinon");
+const { sleep } = require("../src/helpers");
+import { performance } from "perf_hooks";
 
 interface Test {
     key: string;
-    val: number;
+    visited: number[];
 }
-test.cb("should spread per key", t => {
-    t.plan(5);
+test.cb("demux() constructor should be called once per key", t => {
+    t.plan(1);
     const input = [
-        { key: "a", val: 1 },
-        { key: "b", val: 2 },
-        { key: "a", val: 3 },
-        { key: "c", val: 4 },
+        { key: "a", visited: [] },
+        { key: "b", visited: [] },
+        { key: "a", visited: [] },
+        { key: "c", visited: [] },
     ];
-    const results = [
-        { key: "a", val: 2 },
-        { key: "b", val: 3 },
-        { key: "a", val: 4 },
-        { key: "c", val: 5 },
-    ];
-    const destinationStreamKeys = [];
-    let i = 0;
-    const sink = new Writable({
-        objectMode: true,
-        write(chunk, enc, cb) {
-            expect(results).to.deep.include(chunk);
-            expect(input).to.not.deep.include(chunk);
-            t.pass();
-            cb();
-        },
-    });
-    const construct = (destKey: string) => {
-        destinationStreamKeys.push(destKey);
+    const construct = sinon.spy((destKey: string) => {
         const dest = map((chunk: Test) => {
-            return {
-                ...chunk,
-                val: chunk.val + 1,
-            };
+            chunk.visited.push(1);
+            return chunk;
         });
 
-        dest.pipe(sink);
         return dest;
-    };
+    });
 
     const demuxed = demux(construct, { key: "key" }, { objectMode: true });
+
     demuxed.on("finish", () => {
-        expect(destinationStreamKeys).to.deep.equal(["a", "b", "c"]);
+        expect(construct.withArgs("a").callCount).to.equal(1);
+        expect(construct.withArgs("b").callCount).to.equal(1);
+        expect(construct.withArgs("c").callCount).to.equal(1);
         t.pass();
         t.end();
     });
@@ -56,50 +41,34 @@ test.cb("should spread per key", t => {
     demuxed.end();
 });
 
-test.cb("should spread per key using keyBy", t => {
-    t.plan(5);
+test.cb("demux() constructor should be called once per key using keyBy", t => {
+    t.plan(1);
     const input = [
-        { key: "a", val: 1 },
-        { key: "b", val: 2 },
-        { key: "a", val: 3 },
-        { key: "c", val: 4 },
+        { key: "a", visited: [] },
+        { key: "b", visited: [] },
+        { key: "a", visited: [] },
+        { key: "c", visited: [] },
     ];
-    const results = [
-        { key: "a", val: 2 },
-        { key: "b", val: 3 },
-        { key: "a", val: 4 },
-        { key: "c", val: 5 },
-    ];
-    const destinationStreamKeys = [];
-    const sink = new Writable({
-        objectMode: true,
-        write(chunk, enc, cb) {
-            expect(results).to.deep.include(chunk);
-            expect(input).to.not.deep.include(chunk);
-            t.pass();
-            cb();
-        },
-    });
-    const construct = (destKey: string) => {
-        destinationStreamKeys.push(destKey);
+
+    const construct = sinon.spy((destKey: string) => {
         const dest = map((chunk: Test) => {
-            return {
-                ...chunk,
-                val: chunk.val + 1,
-            };
+            chunk.visited.push(1);
+            return chunk;
         });
 
-        dest.pipe(sink);
         return dest;
-    };
+    });
 
     const demuxed = demux(
         construct,
-        { keyBy: (chunk: any) => chunk.key },
+        { keyBy: item => item.key },
         { objectMode: true },
     );
+
     demuxed.on("finish", () => {
-        expect(destinationStreamKeys).to.deep.equal(["a", "b", "c"]);
+        expect(construct.withArgs("a").callCount).to.equal(1);
+        expect(construct.withArgs("b").callCount).to.equal(1);
+        expect(construct.withArgs("c").callCount).to.equal(1);
         t.pass();
         t.end();
     });
@@ -110,17 +79,18 @@ test.cb("should spread per key using keyBy", t => {
 
 test.cb("should emit errors", t => {
     t.plan(2);
+    let index = 0;
     const input = [
-        { key: "a", val: 1 },
-        { key: "b", val: 2 },
-        { key: "a", val: 3 },
-        { key: "a", val: 4 },
+        { key: "a", visited: [] },
+        { key: "b", visited: [] },
+        { key: "a", visited: [] },
+        { key: "a", visited: [] },
     ];
     const results = [
-        { key: "a", val: 2 },
-        { key: "b", val: 3 },
-        { key: "a", val: 4 },
-        { key: "a", val: 5 },
+        { key: "a", visited: [0] },
+        { key: "b", visited: [1] },
+        { key: "a", visited: [2] },
+        { key: "a", visited: [3] },
     ];
     const destinationStreamKeys = [];
     const sink = new Writable({
@@ -131,7 +101,7 @@ test.cb("should emit errors", t => {
             t.pass();
             cb();
         },
-    }).on("unpipe", e => console.log("sink err"));
+    });
 
     const construct = (destKey: string) => {
         destinationStreamKeys.push(destKey);
@@ -139,11 +109,12 @@ test.cb("should emit errors", t => {
             if (chunk.key === "b") {
                 throw new Error("Caught object with key 'b'");
             }
-            return {
-                ...chunk,
-                val: chunk.val + 1,
-            };
-        }).on("error", e => console.log("got err"));
+
+            const _chunk = { ...chunk, visited: [] };
+            _chunk.visited.push(index);
+            index++;
+            return _chunk;
+        }).on("error", () => {});
 
         dest.pipe(sink);
         return dest;
@@ -162,3 +133,374 @@ test.cb("should emit errors", t => {
     input.forEach(event => demuxed.write(event));
     demuxed.end();
 });
+
+test("compose() should emit drain event ~rate * highWaterMark ms for every write that causes backpressure", async t => {
+    t.plan(7);
+    const highWaterMark = 5;
+    const _rate = 25;
+    return new Promise(async (resolve, reject) => {
+        interface Chunk {
+            key: string;
+            mapped: number[];
+        }
+        const sink = new Writable({
+            objectMode: true,
+            write(chunk, encoding, cb) {
+                cb();
+                t.pass();
+                pendingReads--;
+                if (pendingReads === 0) {
+                    resolve();
+                }
+            },
+        });
+        const construct = (destKey: string) => {
+            const first = map(async (chunk: Chunk) => {
+                await sleep(_rate);
+                chunk.mapped.push(1);
+                return chunk;
+            });
+
+            const second = map(async (chunk: Chunk) => {
+                chunk.mapped.push(2);
+                return chunk;
+            });
+
+            first.pipe(second).pipe(sink);
+            return first;
+        };
+        const _demux = demux(
+            construct,
+            { key: "key" },
+            {
+                objectMode: true,
+                highWaterMark,
+            },
+        );
+        _demux.on("error", err => {
+            reject();
+        });
+
+        _demux.on("drain", () => {
+            expect(_demux._writableState.length).to.be.equal(0);
+            expect(performance.now() - start).to.be.greaterThan(_rate);
+            t.pass();
+        });
+
+        const input = [
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+        ];
+        let pendingReads = input.length;
+
+        let start = performance.now();
+        for (const item of input) {
+            const res = _demux.write(item);
+            expect(_demux._writableState.length).to.be.at.most(highWaterMark);
+            if (!res) {
+                start = performance.now();
+                await sleep(100);
+            }
+        }
+    });
+});
+
+test("demux() should emit one drain event when writing 6 items with highWaterMark of 5", t => {
+    t.plan(7);
+    const highWaterMark = 5;
+    return new Promise(async (resolve, reject) => {
+        interface Chunk {
+            key: string;
+            mapped: number[];
+        }
+        const sink = new Writable({
+            objectMode: true,
+            write(chunk, encoding, cb) {
+                cb();
+                t.pass();
+                if (chunk.key === "f") {
+                    resolve();
+                }
+            },
+        });
+        const construct = (destKey: string) => {
+            const first = map(async (chunk: Chunk) => {
+                chunk.mapped.push(1);
+                return chunk;
+            });
+
+            const second = map(async (chunk: Chunk) => {
+                chunk.mapped.push(2);
+                return chunk;
+            });
+
+            first.pipe(second).pipe(sink);
+            return first;
+        };
+        const _demux = demux(
+            construct,
+            { key: "key" },
+            {
+                objectMode: true,
+                highWaterMark,
+            },
+        );
+        _demux.on("error", err => {
+            reject();
+        });
+
+        _demux.on("drain", () => {
+            expect(_demux._writableState.length).to.be.equal(0);
+            t.pass();
+        });
+
+        const input = [
+            { key: "a", mapped: [] },
+            { key: "b", mapped: [] },
+            { key: "c", mapped: [] },
+            { key: "d", mapped: [] },
+            { key: "e", mapped: [] },
+            { key: "f", mapped: [] },
+        ];
+
+        for (const item of input) {
+            const res = _demux.write(item);
+            expect(_demux._writableState.length).to.be.at.most(highWaterMark);
+            if (!res) {
+                await sleep(10);
+            }
+        }
+    });
+});
+
+test.cb(
+    "demux() should emit drain event after 500 ms when writing 5 items that take 100ms to process with a highWaterMark of 5 ",
+    t => {
+        t.plan(6);
+        const _rate = 100;
+        const highWaterMark = 5;
+        interface Chunk {
+            key: string;
+            mapped: number[];
+        }
+        const sink = new Writable({
+            objectMode: true,
+            write(chunk, encoding, cb) {
+                t.pass();
+                cb();
+                if (pendingReads === 0) {
+                    t.end();
+                }
+            },
+        });
+        const construct = (destKey: string) => {
+            const first = map(
+                async (chunk: Chunk) => {
+                    chunk.mapped.push(1);
+                    await sleep(_rate);
+                    return chunk;
+                },
+                { objectMode: true },
+            );
+
+            const second = map(
+                (chunk: Chunk) => {
+                    pendingReads--;
+                    chunk.mapped.push(2);
+                    return chunk;
+                },
+                { objectMode: true, highWaterMark: 1 },
+            );
+
+            first.pipe(second).pipe(sink);
+            return first;
+        };
+        const _demux = demux(
+            construct,
+            { key: "key" },
+            {
+                objectMode: true,
+                highWaterMark,
+            },
+        );
+        _demux.on("error", err => {
+            t.end(err);
+        });
+
+        _demux.on("drain", () => {
+            expect(_demux._writableState.length).to.be.equal(0);
+            expect(performance.now() - start).to.be.greaterThan(
+                _rate * input.length,
+            );
+            t.pass();
+        });
+
+        const input = [
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+        ];
+
+        let pendingReads = input.length;
+        input.forEach(item => {
+            _demux.write(item);
+        });
+        const start = performance.now();
+    },
+);
+test.cb(
+    "demux() should emit drain event immediately when second stream is bottleneck",
+    t => {
+        t.plan(6);
+        const highWaterMark = 5;
+        interface Chunk {
+            key: string;
+            mapped: number[];
+        }
+        const sink = new Writable({
+            objectMode: true,
+            write(chunk, encoding, cb) {
+                t.pass();
+                cb();
+                if (pendingReads === 0) {
+                    t.end();
+                }
+            },
+        });
+        const construct = (destKey: string) => {
+            const first = map(
+                (chunk: Chunk) => {
+                    chunk.mapped.push(1);
+                    return chunk;
+                },
+                { objectMode: true },
+            );
+
+            const second = map(
+                async (chunk: Chunk) => {
+                    pendingReads--;
+                    await sleep(200);
+                    chunk.mapped.push(2);
+                    expect(second._writableState.length).to.be.equal(1);
+                    expect(first._readableState.length).to.equal(pendingReads);
+                    return chunk;
+                },
+                { objectMode: true, highWaterMark: 1 },
+            );
+
+            first.pipe(second).pipe(sink);
+            return first;
+        };
+        const _demux = demux(
+            construct,
+            { key: "key" },
+            {
+                objectMode: true,
+                highWaterMark,
+            },
+        );
+        _demux.on("error", err => {
+            t.end(err);
+        });
+
+        _demux.on("drain", () => {
+            expect(_demux._writableState.length).to.be.equal(0);
+            expect(performance.now() - start).to.be.lessThan(50);
+            t.pass();
+        });
+
+        const input = [
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+        ];
+
+        let pendingReads = input.length;
+        input.forEach(item => {
+            _demux.write(item);
+        });
+        const start = performance.now();
+    },
+);
+
+test("demux() should emit drain event and first should contain up to highWaterMark items in readable state when second is bottleneck", t => {
+    t.plan(6);
+    const highWaterMark = 5;
+    return new Promise(async (resolve, reject) => {
+        interface Chunk {
+            key: string;
+            mapped: number[];
+        }
+        const sink = new Writable({
+            objectMode: true,
+            write(chunk, encoding, cb) {
+                t.pass();
+                cb();
+                if (pendingReads === 0) {
+                    resolve();
+                }
+            },
+        });
+        const construct = (destKey: string) => {
+            const first = map(
+                (chunk: Chunk) => {
+                    expect(first._readableState.length).to.be.at.most(2);
+                    chunk.mapped.push(1);
+                    return chunk;
+                },
+                { objectMode: 2, highWaterMark: 2 },
+            );
+
+            const second = map(
+                async (chunk: Chunk) => {
+                    chunk.mapped.push(2);
+                    expect(second._writableState.length).to.be.equal(1);
+                    await sleep(100);
+                    pendingReads--;
+                    return chunk;
+                },
+                { objectMode: 2, highWaterMark: 2 },
+            );
+
+            first.pipe(second).pipe(sink);
+            return first;
+        };
+        const _demux = demux(
+            construct,
+            { key: "key" },
+            {
+                objectMode: true,
+                highWaterMark,
+            },
+        );
+        _demux.on("error", err => {
+            reject();
+        });
+
+        _demux.on("drain", () => {
+            expect(_demux._writableState.length).to.be.equal(0);
+            t.pass();
+        });
+
+        const input = [
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+            { key: "a", mapped: [] },
+        ];
+        let pendingReads = input.length;
+
+        input.forEach(item => {
+            _demux.write(item);
+        });
+    });
+});
diff --git a/yarn.lock b/yarn.lock
index ee57991..ba435ef 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -326,6 +326,35 @@
   dependencies:
     arrify "^1.0.1"
 
+"@sinonjs/commons@^1", "@sinonjs/commons@^1.3.0", "@sinonjs/commons@^1.4.0":
+  version "1.6.0"
+  resolved "https://registry.yarnpkg.com/@sinonjs/commons/-/commons-1.6.0.tgz#ec7670432ae9c8eb710400d112c201a362d83393"
+  integrity sha512-w4/WHG7C4WWFyE5geCieFJF6MZkbW4VAriol5KlmQXpAQdxvV0p26sqNZOW6Qyw6Y0l9K4g+cHvvczR2sEEpqg==
+  dependencies:
+    type-detect "4.0.8"
+
+"@sinonjs/formatio@^3.2.1":
+  version "3.2.1"
+  resolved "https://registry.yarnpkg.com/@sinonjs/formatio/-/formatio-3.2.1.tgz#52310f2f9bcbc67bdac18c94ad4901b95fde267e"
+  integrity sha512-tsHvOB24rvyvV2+zKMmPkZ7dXX6LSLKZ7aOtXY6Edklp0uRcgGpOsQTTGTcWViFyx4uhWc6GV8QdnALbIbIdeQ==
+  dependencies:
+    "@sinonjs/commons" "^1"
+    "@sinonjs/samsam" "^3.1.0"
+
+"@sinonjs/samsam@^3.1.0", "@sinonjs/samsam@^3.3.3":
+  version "3.3.3"
+  resolved "https://registry.yarnpkg.com/@sinonjs/samsam/-/samsam-3.3.3.tgz#46682efd9967b259b81136b9f120fd54585feb4a"
+  integrity sha512-bKCMKZvWIjYD0BLGnNrxVuw4dkWCYsLqFOUWw8VgKF/+5Y+mE7LfHWPIYoDXowH+3a9LsWDMo0uAP8YDosPvHQ==
+  dependencies:
+    "@sinonjs/commons" "^1.3.0"
+    array-from "^2.1.1"
+    lodash "^4.17.15"
+
+"@sinonjs/text-encoding@^0.7.1":
+  version "0.7.1"
+  resolved "https://registry.yarnpkg.com/@sinonjs/text-encoding/-/text-encoding-0.7.1.tgz#8da5c6530915653f3a1f38fd5f101d8c3f8079c5"
+  integrity sha512-+iTbntw2IZPb/anVDbypzfQa+ay64MW0Zo8aJ8gZPWMMK6/OubMVb6lUPMagqjOPnmtauXnFCACVl3O7ogjeqQ==
+
 "@types/chai@^4.1.7":
   version "4.2.0"
   resolved "https://registry.yarnpkg.com/@types/chai/-/chai-4.2.0.tgz#2478260021408dec32c123a7cad3414beb811a07"
@@ -355,6 +384,11 @@
   resolved "https://registry.yarnpkg.com/@types/node/-/node-12.7.2.tgz#c4e63af5e8823ce9cc3f0b34f7b998c2171f0c44"
   integrity sha512-dyYO+f6ihZEtNPDcWNR1fkoTDf3zAK3lAABDze3mz6POyIercH0lEUawUFXlG8xaQZmm1yEBON/4TsYv/laDYg==
 
+"@types/sinon@^7.0.13":
+  version "7.0.13"
+  resolved "https://registry.yarnpkg.com/@types/sinon/-/sinon-7.0.13.tgz#ca039c23a9e27ebea53e0901ef928ea2a1a6d313"
+  integrity sha512-d7c/C/+H/knZ3L8/cxhicHUiTDxdgap0b/aNJfsmLwFu/iOP17mdgbQsbHA3SJmrzsjD0l3UEE5SN4xxuz5ung==
+
 abbrev@1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/abbrev/-/abbrev-1.1.1.tgz#f8f2c887ad10bf67f634f005b6987fed3179aac8"
@@ -452,6 +486,11 @@ array-find-index@^1.0.1:
   resolved "https://registry.yarnpkg.com/array-find-index/-/array-find-index-1.0.2.tgz#df010aa1287e164bbda6f9723b0a96a1ec4187a1"
   integrity sha1-3wEKoSh+Fku9pvlyOwqWoexBh6E=
 
+array-from@^2.1.1:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/array-from/-/array-from-2.1.1.tgz#cfe9d8c26628b9dc5aecc62a9f5d8f1f352c1195"
+  integrity sha1-z+nYwmYoudxa7MYqn12PHzUsEZU=
+
 array-union@^1.0.1, array-union@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/array-union/-/array-union-1.0.2.tgz#9a34410e4f4e3da23dea375be5be70f24778ec39"
@@ -1113,7 +1152,7 @@ detect-libc@^1.0.2:
   resolved "https://registry.yarnpkg.com/detect-libc/-/detect-libc-1.0.3.tgz#fa137c4bd698edf55cd5cd02ac559f91a4c4ba9b"
   integrity sha1-+hN8S9aY7fVc1c0CrFWfkaTEups=
 
-diff@^3.2.0:
+diff@^3.2.0, diff@^3.5.0:
   version "3.5.0"
   resolved "https://registry.yarnpkg.com/diff/-/diff-3.5.0.tgz#800c0dd1e0a8bfbc95835c202ad220fe317e5a12"
   integrity sha512-A46qtFgd+g7pDZinpnwiRJtxbC1hpgf0uzP3iG89scHk0AUC7A1TGxf5OiiOUv/JMZR8GOt8hL900hV0bOy5xA==
@@ -1826,6 +1865,11 @@ is-windows@^1.0.2:
   resolved "https://registry.yarnpkg.com/is-windows/-/is-windows-1.0.2.tgz#d1850eb9791ecd18e6182ce12a30f396634bb19d"
   integrity sha512-eXK1UInq2bPmjyX6e3VHIzMLobc4J94i4AWn+Hpq3OU5KkrRC96OAcR3PRJ/pGu6m8TRnBHP9dkXQVsT/COVIA==
 
+isarray@0.0.1:
+  version "0.0.1"
+  resolved "https://registry.yarnpkg.com/isarray/-/isarray-0.0.1.tgz#8a18acfca9a8f4177e09abfc6038939b05d1eedf"
+  integrity sha1-ihis/Kmo9Bd+Cav8YDiTmwXR7t8=
+
 isarray@1.0.0, isarray@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/isarray/-/isarray-1.0.0.tgz#bb935d48582cba168c06834957a54a3e07124f11"
@@ -1893,6 +1937,11 @@ json5@^2.1.0:
   dependencies:
     minimist "^1.2.0"
 
+just-extend@^4.0.2:
+  version "4.0.2"
+  resolved "https://registry.yarnpkg.com/just-extend/-/just-extend-4.0.2.tgz#f3f47f7dfca0f989c55410a7ebc8854b07108afc"
+  integrity sha512-FrLwOgm+iXrPV+5zDU6Jqu4gCRXbWEQg2O3SKONsWE4w7AXFRkryS53bpWdaL9cNol+AmR3AEYz6kn+o0fCPnw==
+
 kind-of@^3.0.2, kind-of@^3.0.3, kind-of@^3.2.0:
   version "3.2.2"
   resolved "https://registry.yarnpkg.com/kind-of/-/kind-of-3.2.2.tgz#31ea21a734bab9bbb0f32466d893aea51e4a3c64"
@@ -2011,7 +2060,7 @@ lodash.merge@^4.6.1:
   resolved "https://registry.yarnpkg.com/lodash.merge/-/lodash.merge-4.6.2.tgz#558aa53b43b661e1925a0afdfa36a9a1085fe57a"
   integrity sha512-0KpjqXRVvrYyCsX1swR/XTK0va6VQkQM6MNo7PqW77ByjAhoARA8EfrP1N4+KlKj8YS0ZUCtRT/YUuhyYDujIQ==
 
-lodash@^4.17.13:
+lodash@^4.17.13, lodash@^4.17.15:
   version "4.17.15"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
   integrity sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A==
@@ -2023,6 +2072,11 @@ log-symbols@^2.2.0:
   dependencies:
     chalk "^2.0.1"
 
+lolex@^4.1.0, lolex@^4.2.0:
+  version "4.2.0"
+  resolved "https://registry.yarnpkg.com/lolex/-/lolex-4.2.0.tgz#ddbd7f6213ca1ea5826901ab1222b65d714b3cd7"
+  integrity sha512-gKO5uExCXvSm6zbF562EvM+rd1kQDnB9AZBbiQVzf1ZmdDpxUSvpnAaVOP83N/31mRK8Ml8/VE8DMvsAZQ+7wg==
+
 loud-rejection@^1.0.0, loud-rejection@^1.2.0:
   version "1.6.0"
   resolved "https://registry.yarnpkg.com/loud-rejection/-/loud-rejection-1.6.0.tgz#5b46f80147edee578870f086d04821cf998e551f"
@@ -2253,6 +2307,17 @@ needle@^2.2.1:
     iconv-lite "^0.4.4"
     sax "^1.2.4"
 
+nise@^1.5.2:
+  version "1.5.2"
+  resolved "https://registry.yarnpkg.com/nise/-/nise-1.5.2.tgz#b6d29af10e48b321b307e10e065199338eeb2652"
+  integrity sha512-/6RhOUlicRCbE9s+94qCUsyE+pKlVJ5AhIv+jEE7ESKwnbXqulKZ1FYU+XAtHHWE9TinYvAxDUJAb912PwPoWA==
+  dependencies:
+    "@sinonjs/formatio" "^3.2.1"
+    "@sinonjs/text-encoding" "^0.7.1"
+    just-extend "^4.0.2"
+    lolex "^4.1.0"
+    path-to-regexp "^1.7.0"
+
 node-pre-gyp@^0.12.0:
   version "0.12.0"
   resolved "https://registry.yarnpkg.com/node-pre-gyp/-/node-pre-gyp-0.12.0.tgz#39ba4bb1439da030295f899e3b520b7785766149"
@@ -2545,6 +2610,13 @@ path-parse@^1.0.6:
   resolved "https://registry.yarnpkg.com/path-parse/-/path-parse-1.0.6.tgz#d62dbb5679405d72c4737ec58600e9ddcf06d24c"
   integrity sha512-GSmOT2EbHrINBf9SR7CDELwlJ8AENk3Qn7OikK4nFYAu3Ote2+JYNVvkpAEQm3/TLNEJFD/xZJjzyxg3KBWOzw==
 
+path-to-regexp@^1.7.0:
+  version "1.7.0"
+  resolved "https://registry.yarnpkg.com/path-to-regexp/-/path-to-regexp-1.7.0.tgz#59fde0f435badacba103a84e9d3bc64e96b9937d"
+  integrity sha1-Wf3g9DW62suhA6hOnTvGTpa5k30=
+  dependencies:
+    isarray "0.0.1"
+
 path-type@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/path-type/-/path-type-3.0.0.tgz#cef31dc8e0a1a3bb0d105c0cd97cf3bf47f4e36f"
@@ -2906,6 +2978,19 @@ signal-exit@^3.0.0, signal-exit@^3.0.2:
   resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.2.tgz#b5fdc08f1287ea1178628e415e25132b73646c6d"
   integrity sha1-tf3AjxKH6hF4Yo5BXiUTK3NkbG0=
 
+sinon@^7.4.2:
+  version "7.4.2"
+  resolved "https://registry.yarnpkg.com/sinon/-/sinon-7.4.2.tgz#ecd54158fef2fcfbdb231a3fa55140e8cb02ad6c"
+  integrity sha512-pY5RY99DKelU3pjNxcWo6XqeB1S118GBcVIIdDi6V+h6hevn1izcg2xv1hTHW/sViRXU7sUOxt4wTUJ3gsW2CQ==
+  dependencies:
+    "@sinonjs/commons" "^1.4.0"
+    "@sinonjs/formatio" "^3.2.1"
+    "@sinonjs/samsam" "^3.3.3"
+    diff "^3.5.0"
+    lolex "^4.2.0"
+    nise "^1.5.2"
+    supports-color "^5.5.0"
+
 slash@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/slash/-/slash-1.0.0.tgz#c41f2f6c39fc16d1cd17ad4b5d896114ae470d55"
@@ -3126,7 +3211,7 @@ supertap@^1.0.0:
     serialize-error "^2.1.0"
     strip-ansi "^4.0.0"
 
-supports-color@^5.3.0:
+supports-color@^5.3.0, supports-color@^5.5.0:
   version "5.5.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-5.5.0.tgz#e2e69a44ac8772f78a1ec0b35b689df6530efc8f"
   integrity sha512-QjVjwdXIt408MIiAqCX4oUKsgU2EqAGzs2Ppkm4aQYbjm+ZEWEcW4SfFNTr4uMNZma0ey4f5lgLrkB0aX0QMow==
@@ -3281,7 +3366,7 @@ tsutils@^2.29.0:
   dependencies:
     tslib "^1.8.1"
 
-type-detect@^4.0.0, type-detect@^4.0.5:
+type-detect@4.0.8, type-detect@^4.0.0, type-detect@^4.0.5:
   version "4.0.8"
   resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.0.8.tgz#7646fb5f18871cfbb7749e69bd39a6388eb7450c"
   integrity sha512-0fr/mIH1dlO+x7TlcMy+bIDqKPsw/70tVyeHW787goQjhmqaZe10uwLujubK9q9Lg6Fiho1KUKDYz0Z7k7g5/g==