public HTTPClient SetRequest(HTTPRequest request)
 {
   _request = request;
   return this;
 }
 public HTTPClient(HTTPRequest request = null,
     HTTPResponseHandler responseHandler = null)
 {
   _connectionID = Bindings.INVALID_CONNECTION_ID;
   _state = ConnectionState.Initialized;
   _connectionTimeout = DefaultConnectionTimeout;
   _error = null;
   _requestSent = false;
   _request = request;
   _response = null;
   _responseHandler = responseHandler;
 }