feat(smartduplex): improve backpressure handling and web/node stream interoperability

ts/smartstream.classes.streamwrapper.ts

@@ -1,8 +1,5 @@
 import * as plugins from './smartstream.plugins.js';
 
-// interfaces
-import { Transform } from 'stream';
-
 export interface IErrorFunction {
   (err: Error): any;
 }
@@ -82,15 +79,17 @@ export class StreamWrapper {
 
     this.streamStartedDeferred.resolve();
 
-    finalStream.on('end', () => {
-      done.resolve();
-    });
-    finalStream.on('close', () => {
-      done.resolve();
-    });
-    finalStream.on('finish', () => {
-      done.resolve();
-    });
+    let resolved = false;
+    const safeResolve = () => {
+      if (!resolved) {
+        resolved = true;
+        done.resolve();
+      }
+    };
+
+    finalStream.on('end', safeResolve);
+    finalStream.on('close', safeResolve);
+    finalStream.on('finish', safeResolve);
     return done.promise;
   }
 }