diff --git a/package.json b/package.json
index f85ed1a..06f9734 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@jogogo/mhysa",
-    "version": "0.0.1-beta.2",
+    "version": "0.0.1-beta.4",
     "description": "Streams and event emitter utils for Node.js",
     "keywords": [
         "promise",
diff --git a/src/functions/demux.ts b/src/functions/demux.ts
index 66ee487..9e26594 100644
--- a/src/functions/demux.ts
+++ b/src/functions/demux.ts
@@ -51,10 +51,10 @@ class Demux extends Writable {
         this.streamsByKey = {};
     }
 
-    public _write(chunk: any, encoding: any, cb: any) {
+    public async _write(chunk: any, encoding: any, cb: any) {
         const destKey = this.demuxer(chunk);
         if (this.streamsByKey[destKey] === undefined) {
-            this.streamsByKey[destKey] = this.construct(destKey);
+            this.streamsByKey[destKey] = await this.construct(destKey);
         }
         if (!this.streamsByKey[destKey].write(chunk, encoding)) {
             this.streamsByKey[destKey].once("drain", () => {