fix: forward dispatch return value

lib/dispatcher/dispatcher.js

@@ -39,6 +39,11 @@ class Dispatcher extends EventEmitter {
   }
 }
 
+const kOnDrain = Symbol('onDrain')
+const kOnConnect = Symbol('onConnect')
+const kOnDisconnect = Symbol('onDisconnect')
+const kOnConnectionError = Symbol('onConnectionError')
+
 class ComposedDispatcher extends Dispatcher {
   #dispatcher = null
   #dispatch = null
@@ -47,10 +52,21 @@ class ComposedDispatcher extends Dispatcher {
     super()
     this.#dispatcher = dispatcher
     this.#dispatch = dispatch
+
+    this[kOnDrain] = () => this.emit('drain')
+    this[kOnConnect] = () => this.emit('connect')
+    this[kOnDisconnect] = () => this.emit('disconnect')
+    this[kOnConnectionError] = () => this.emit('connectionError')
+
+    this.#dispatcher
+      .on('drain', this[kOnDrain])
+      .on('connect', this[kOnConnect])
+      .on('disconnect', this[kOnDisconnect])
+      .on('connectionError', this[kOnConnectionError])
   }
 
   dispatch (...args) {
-    this.#dispatch(...args)
+    return this.#dispatch(...args)
   }
 
   close (...args) {