@Override
  public long getRPCStartTime() {
    if (getState() != State.RUNNING) {
      return -1;
    }
    return rpcStartTime;
  }
Accesses the start time for the currently running RPC on the monitored Handler.
@return the start timestamp or -1 if there is no RPC currently running.
hbase-server/src/main/java/org/apache/hadoop/hbase/monitoring/MonitoredRPCHandlerImpl.java