@Override
  public IsInMaintenanceModeResponse isMasterInMaintenanceMode(final RpcController controller,
    final IsInMaintenanceModeRequest request) throws ServiceException {
    IsInMaintenanceModeResponse.Builder response = IsInMaintenanceModeResponse.newBuilder();
    response.setInMaintenanceMode(server.isInMaintenanceMode());
    return response.build();
  }
Triggers an asynchronous attempt to take a snapshot. {@inheritDoc}
hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java