stream: add writableCorked to Duplex

PR-URL: #29053
Reviewed-By: Anna Henningsen <[email protected]>

Author: addaleax

lib/_stream_duplex.js

@@ -108,6 +108,16 @@ Object.defineProperty(Duplex.prototype, 'writableFinished', {
   }
 });
 
+Object.defineProperty(Duplex.prototype, 'writableCorked', {
+  // Making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get() {
+    return this._writableState ? this._writableState.corked : 0;
+  }
+});
+
 Object.defineProperty(Duplex.prototype, 'writableEnded', {
   // Making it explicit this property is not enumerable
   // because otherwise some prototype manipulation in