Add Resource package.

lib/src/io.dart

 // Copyright (c) 2015, 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.
 
 // dart:io based strategy for loading resources.
 
 import "dart:io" show File, HttpClient, HttpClientRequest, HttpClientResponse;
 import "dart:async" show Future, Stream;
 import "dart:convert" show Encoding, UTF8;
 import "package:typed_data/typed_buffers.dart" show Uint8Buffer;
 
+// TODO(lrn): Add support for "data:" URIs.
+
+/// Read the bytes of a URI as a stream of bytes.
 Stream<List<int>> readAsStream(Uri uri) async* {
   if (uri.scheme == "file") {
     yield* new File.fromUri(uri).openRead();
     return;
   }
   if (uri.scheme == "http" || uri.scheme == "https") {
     HttpClientResponse response = await _httpGet(uri);
     yield* response;
     return;
   }
   throw new UnsupportedError("Unsupported scheme: $uri");
 }
 
+/// Read the bytes of a URI as a list of bytes.
 Future<List<int>> readAsBytes(Uri uri) async {
   if (uri.scheme == "file") {
     return new File.fromUri(uri).readAsBytes();
   }
   if (uri.scheme == "http" || uri.scheme == "https") {
     HttpClientResponse response = await _httpGet(uri);
     Uint8Buffer buffer = new Uint8Buffer();
     await for (var bytes in response) {
       buffer.addAll(bytes);
     }
     return buffer.toList();
   }
   throw new UnsupportedError("Unsupported scheme: $uri");
 }
 
+/// Read the bytes of a URI as a string.
+///
+/// Encoding defaults to UTF-8.
 Future<String> readAsString(Uri uri, Encoding encoding) async {
   if (encoding == null) encoding = UTF8;
   if (uri.scheme == "file") {
     return new File.fromUri(uri).readAsString(encoding: encoding);
   }
   if (uri.scheme == "http" || uri.scheme == "https") {
     HttpClientResponse response = await _httpGet(uri);
     Uint8Buffer buffer = new Uint8Buffer();
     await for (var bytes in response) {
       buffer.addAll(bytes);
     }
     new String.fromCharCodes(buffer.toList());
   }
   throw new UnsupportedError("Unsupported scheme: $uri");
 }
 
 Future<HttpClientResponse> _httpGet(Uri uri) async {
   HttpClientRequest request = await new HttpClient().getUrl(uri);
   return await request.close();
 }