public long getStartApplyNanos() {
      if (startApplyNanos == 0) {
        return System.nanoTime();
      }
      return startApplyNanos;
    }
Reset all data to initial status and set connectorRebootTimes properly. This method is called
when receiver identifies connector has rebooted.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/receiver/protocol/pipeconsensus/PipeConsensusReceiver.java