anchor.diff:        var headers;
         if (downloadRange != null) {
           headers = {
  +          'user-agent' : USER_AGENT_STRING,
             'content-type' : CONTENT_TYPE_JSON_UTF8,
             'content-length' : '$length',
             'range' :  'bytes=${downloadRange.start}-${downloadRange.end}',
           };
         } else {
           headers = {
  +          'user-agent' : USER_AGENT_STRING,
             'content-type' : CONTENT_TYPE_JSON_UTF8,
             'content-length' : '$length',
           };
  
positive.code: import "package:crypto/crypto.dart" as crypto;
  import "../common/common.dart" as common_external;
  import "package:http/http.dart" as http;
  """ + r"""
  const CONTENT_TYPE_JSON_UTF8 = 'application/json; charset=utf-8';
  
  
negative.code:     }
  
      var headers = {
          'user-agent' : USER_AGENT_STRING,
          'content-type' : _uploadMedia.contentType,
          'content-length' : '${chunk.length}',
          'content-range' :
  