Don't die because we write empty arrays to cURL.

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:async';
 import 'dart:io';
 import 'dart:isolate';
@@ skipping 581 matching lines @@
 
   _OutputStreamConsumer(this._outputStream);
 
   Future consume(Stream<List<int>> stream) {
     // TODO(nweiz): we have to manually keep track of whether or not the
     // completer has completed since the output stream could signal an error
     // after close() has been called but before it has shut down internally. See
     // the following TODO.
     var completed = false;
     var completer = new Completer();
-    stream.listen((data) => _outputStream.write(data), onDone: () {
+    stream.listen((data) {
+      // Writing empty data to a closed stream can cause errors.
+      if (data.isEmpty) return;
+
+      // TODO(nweiz): remove this try/catch when issue 7836 is fixed.
+      try {
+        _outputStream.write(data);
+      } catch (e, stack) {
+        if (!completed) completer.completeError(e, stack);
+        completed = true;
+      }
+    }, onDone: () {
       _outputStream.close();
       // TODO(nweiz): wait until _outputStream.onClosed is called once issue
       // 7761 is fixed.
       if (!completed) completer.complete(null);
       completed = true;
     });
 
     _outputStream.onError = (e) {
       if (!completed) completer.completeError(e);
       completed = true;
@@ skipping 404 matching lines @@
 Directory _getDirectory(entry) {
   if (entry is Directory) return entry;
   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);
 }