pkg/http: Removed uses of Chain.track

lib/src/io_client.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 io_client;
 
 import 'dart:async';
 
-import 'package:stack_trace/stack_trace.dart';
-
 import 'base_client.dart';
 import 'base_request.dart';
 import 'exception.dart';
 import 'io.dart' as io;
 import 'streamed_response.dart';
 
 /// A `dart:io`-based HTTP client.
 ///
 /// This is the default client when running on the command line.
 class IOClient extends BaseClient {
@@ skipping 13 matching lines @@
       _inner = innerClient;
     } else {
       _inner = io.newHttpClient();
     }
   }
 
   /// Sends an HTTP request and asynchronously returns the response.
   Future<StreamedResponse> send(BaseRequest request) {
     var stream = request.finalize();
 
-    return Chain.track(_inner.openUrl(request.method, request.url))
+    return _inner.openUrl(request.method, request.url)
         .then((ioRequest) {
       var contentLength = request.contentLength == null ?
           -1 : request.contentLength;
       ioRequest
           ..followRedirects = request.followRedirects
           ..maxRedirects = request.maxRedirects
           ..contentLength = contentLength
           ..persistentConnection = request.persistentConnection;
       request.headers.forEach((name, value) {
         ioRequest.headers.set(name, value);
       });
-      return Chain.track(stream.pipe(ioRequest));
+      return stream.pipe(ioRequest);
     }).then((response) {
       var headers = {};
       response.headers.forEach((key, values) {
         headers[key] = values.join(',');
       });
 
       var contentLength = response.contentLength == -1 ?
           null : response.contentLength;
       return new StreamedResponse(
           response.handleError((error) =>
@@ skipping 12 matching lines @@
     });
   }
 
   /// Closes the client. This terminates all active connections. If a client
   /// remains unclosed, the Dart process may not terminate.
   void close() {
     if (_inner != null) _inner.close(force: true);
     _inner = null;
   }
 }