pipeInputToInput should be resilient to stream closure.

utils/pub/io.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Helper functionality to make working with IO easier.
  */
 library io;
 
 import 'dart:io';
@@ skipping 601 matching lines @@
  * Takes all input from [source] and writes it to [sink].
  *
  * Returns a future that completes when [source] is closed.
  */
 Future pipeInputToInput(InputStream source, ListInputStream sink) {
   var completer = new Completer();
   source.onClosed = () {
     sink.markEndOfStream();
     completer.complete(null);
   };
-  source.onData = () => sink.write(source.read());
+  source.onData = () {
+    // Even if the sink is closed and we aren't going to do anything with more
+    // data, we still need to drain it from source to work around issue 7218.
+    var data = source.read();
+    if (!sink.closed) sink.write(data);
+  };
   // TODO(nweiz): propagate this error to the sink. See issue 3657.
   source.onError = (e) { throw e; };
   return completer.future;
 }
 
 /**
  * Buffers all input from an InputStream and returns it as a future.
  */
 Future<List<int>> consumeInputStream(InputStream stream) {
   if (stream.closed) return new Future.immediate(<int>[]);
@@ skipping 502 matching lines @@
   return new Directory(entry);
 }
 
 /**
  * Gets a [Uri] for [uri], which can either already be one, or be a [String].
  */
 Uri _getUri(uri) {
   if (uri is Uri) return uri;
   return new Uri.fromString(uri);
 }