Add an HTTP library that wraps dart:io.

pkg/http/lib/src/streamed_response.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.
+
+library streamed_response;
+
+import 'dart:io';
+
+import 'base_response.dart';
+
+/// An HTTP response where the response body is received asynchronously after
+/// the headers have been received.
+class StreamedResponse extends BaseResponse {
+  /// The stream from which the response body data can be read.
+  final InputStream stream;
+
+  /// Creates a new streaming response.
+  StreamedResponse(
+      this.stream,
+      int statusCode,
+      int contentLength,
+      {Map<String, String> headers: const <String>{},
+       bool isRedirect: false,
+       bool persistentConnection: true,
+       String reasonPhrase})
+    : super(
+        statusCode,
+        contentLength,
+        headers: headers,
+        isRedirect: isRedirect,
+        persistentConnection: persistentConnection,
+        reasonPhrase: reasonPhrase);
+}