Update pkg/http to use the new async APIs.

pkg/http/lib/src/byte_stream.dart

+// Copyright (c) 2013, 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.
+
+library byte_stream;
+
+import 'dart:async';
+import 'dart:io';
+import 'dart:scalarlist';
+
+import 'utils.dart';
+
+/// A stream of chunks of bytes representing a single piece of data.
+class ByteStream extends StreamView<List<int>> {
+  ByteStream(Stream<List<int>> stream)
+    : super(stream);
+
+  /// Returns a single-subscription byte stream that will emit the given bytes
+  /// in a single chunk.
+  factory ByteStream.fromBytes(List<int> bytes) =>
+    new ByteStream(streamFromIterable([bytes]));
+
+  /// Collects the data of this stream in a [Uint8List].
+  Future<Uint8List> toBytes() {
+    /// TODO(nweiz): use BufferList when issue 6409 is fixed.
+    return reduce(<int>[], (buffer, chunk) {
+      buffer.addAll(chunk);
+      return buffer;
+    }).then(toUint8List);
+  }
+
+  /// Collect the data of this stream in a [String], decoded according to
+  /// [encoding], which defaults to `Encoding.UTF_8`.
+  Future<String> bytesToString([Encoding encoding=Encoding.UTF_8]) =>
+      toBytes().then((bytes) => decodeString(bytes, encoding));
+}