Add a Peer class to json_rpc_2.

pkg/json_rpc_2/lib/src/client.dart

 // Copyright (c) 2014, 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 json_rpc_2.client;
 
 import 'dart:async';
 
 import 'package:stack_trace/stack_trace.dart';
 
@@ skipping 41 matching lines @@
   ///
   /// If [responses] is a [StreamSink] as well as a [Stream], [requests] may be
   /// omitted.
   ///
   /// Note that the client won't begin listening to [responses] until
   /// [Client.listen] is called.
   Client.withoutJson(Stream responses, [StreamSink requests])
       : _streams = new TwoWayStream.withoutJson(
             "Client", responses, "responses", requests, "requests");
 
-  /// Users of the library should not use this constructor.
-  Client.internal(this._streams);
-
   /// Starts listening to the underlying stream.
   ///
   /// Returns a [Future] that will complete when the stream is closed or when it
   /// has an error.
   ///
   /// [listen] may only be called once.
   Future listen() => _streams.listen(_handleResponse);
 
   /// Closes the server's request sink and response subscription.
   ///
@@ skipping 114 matching lines @@
     if (response.containsKey("result")) return true;
 
     if (!response.containsKey("error")) return false;
     var error = response["error"];
     if (error is! Map) return false;
     if (error["code"] is! int) return false;
     if (error["message"] is! String) return false;
     return true;
   }
 }