code:         public void sendRequest(DiscoveryNode node, long requestId, String action, TransportRequest request, TransportRequestOptions options) throws IOException, TransportException {
              if (recoveryActionToBlock.equals(action) || requestBlocked.getCount() == 0) {
                  logger.info("--> preventing {} request", action);
                  requestBlocked.countDown();
                  if (dropRequests) {
                      return;
                  }
                  throw new ConnectTransportException(node, "DISCONNECT: prevented " + action + " request");
              }
              transport.sendRequest(node, requestId, action, request, options);
          }
      }
  }
  