anchor.diff:  library bwu_docker.src.remote_api.dart;
   
   import 'dart:convert' show JSON;
  -import 'dart:async' show Future, Stream;
  +import 'dart:async' show Future, Stream, ByteStream;
   import 'package:http/http.dart' as http;
   import 'data_structures.dart';
   
  
positive.code:   /// 200 – no error, no upgrade header found
    /// 404 – no such container
    /// 500 – server error
    Future<LogResponse> logs(Container container, {bool follow, bool stdout,
        bool stderr, bool timestamps, dynamic tail}) async {
      assert(stdout == true || stderr == true);
      final query = {};
      if (follow != null) query['follow']= follow.toString();
      if (stdout != null) query['stdout']= stdout.toString();
      if (stderr != null) query['stderr']= stderr.toString();
      if (timestamps != null) query['timestamps'] = timestamps.toString();
      if (tail != null) {
        assert(tail == 'all' || tail is int);
        query['tail'] = tail.toString();
      }
  
      final Map response = await _get('/containers/${container.id}/logs', query: query);
      return new LogResponse.fromJson(response);
    }
  }
  
  
negative.code:     return null;
    }
  
    /// Post request expecting a streamed response.
    Future<Stream> _postStream(String path,
        {Map json, Map<String, String> query}) async {
      String data;
      if (json != null) {
        data = JSON.encode(json);
      }
      final url = new Uri(
          scheme: 'http',
          host: host,
          port: port,
          path: path,
          queryParameters: query);
      final request = new http.Request('GET', url)
        ..body = data
        ..headers.addAll(headers);
      final http.StreamedResponse response =
          await request.send().then(http.Response.fromStream);
      if (response.statusCode < 200 || response.statusCode >= 300) {
        throw 'ERROR: ${response.statusCode} - ${response.reasonPhrase}';
      }
      return response.stream;
    }
  
    Future<dynamic> _get(String path, {Map<String, String> query}) async {
      final url = new Uri(
          scheme: 'http',
  