@Override
  public ReportRegionStateTransitionResponse reportRegionStateTransition(RpcController c,
    ReportRegionStateTransitionRequest req) throws ServiceException {
    try {
      server.checkServiceStarted();
      for (RegionServerStatusProtos.RegionStateTransition transition : req.getTransitionList()) {
        long procId =
          transition.getProcIdCount() > 0 ? transition.getProcId(0) : Procedure.NO_PROC_ID;
        // -1 is less than any possible MasterActiveCode
        long initiatingMasterActiveTime = transition.hasInitiatingMasterActiveTime()
          ? transition.getInitiatingMasterActiveTime()
          : -1;
        throwOnOldMaster(procId, initiatingMasterActiveTime);
      }
      return server.getAssignmentManager().reportRegionStateTransition(req);
    } catch (IOException ioe) {
      throw new ServiceException(ioe);
    }
  }
Triggers an asynchronous attempt to take a snapshot. {@inheritDoc}
hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java