anchor.diff:        mimeType: 'application/x-amf',
         sendData: new AMF3Output([CM], messageOutputWriter).writeObject(),
         responseType: 'arraybuffer',
  -      requestHeaders: <String, String>{'Content-Type': 'application/x-amf'}
  +      requestHeaders: _HEADERS
       );
       
       if (request.response is ByteBuffer) {
  
positive.code:       mimeType: 'application/x-amf',
        sendData: new AMF3Output([CM], messageOutputWriter).writeObject(),
        responseType: 'arraybuffer',
        requestHeaders: <String, String>{'Content-Type': 'application/x-amf'}
      );
      
      if (request.response is ByteBuffer)
  
negative.code: class LongPollChannel extends AMFChannel {
    
    static const List<String> _LONG_POLLING = const <String>['long-polling'];
    static const Map<String, String> _HEADERS = const <String, String>{'Content-Type': 'application/x-amf'};
    
    final String endPoint;
    final String url;
  