Make IOSink implement StringSink

pkg/http/lib/src/request.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 request;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:scalarlist';
 import 'dart:uri';
@@ skipping 31 matching lines @@
   ///
   /// If the `charset` parameter's value is not a known [Encoding], reading this
   /// will throw a [FormatException].
   ///
   /// If the request has a `Content-Type` header, setting this will set the
   /// charset parameter on that header.
   Encoding get encoding {
     if (_contentType == null || _contentType.charset == null) {
       return _defaultEncoding;
     }
-    return requiredEncodingForCharset(_contentType.charset);
+    var encoding = Encoding.fromName(_contentType.charset);
+    if (encoding == null) {
+      throw new FormatException(
+          'Unsupported encoding "${_contentType.charset}".');
+    }
+    return encoding;
   }
 
   set encoding(Encoding value) {
     _checkFinalized();
     _defaultEncoding = value;
     var contentType = _contentType;
     if (contentType != null) {
       contentType = new ContentType(contentType.primaryType,
                                     contentType.subType,
                                     charset: value.name,
@@ skipping 97 matching lines @@
   set _contentType(ContentType value) {
     headers[HttpHeaders.CONTENT_TYPE] = value.toString();
   }
 
   /// Throw an error if this request has been finalized.
   void _checkFinalized() {
     if (!finalized) return;
     throw new StateError("Can't modify a finalized Request.");
   }
 }