code: private static void fireSendingRequestEvent(OperationContext opContext, HttpURLConnection request,
              RequestResult result) {
          if (opContext.getSendingRequestEventHandler().hasListeners()
                  || OperationContext.getGlobalSendingRequestEventHandler().hasListeners()) {
              SendingRequestEvent event = new SendingRequestEvent(opContext, request, result);
              opContext.getSendingRequestEventHandler().fireEvent(event);
              OperationContext.getGlobalSendingRequestEventHandler().fireEvent(event);
          }
      }
docs: Fires events representing that a request will be sent.