private boolean isClientCellBlockSupport(RpcCallContext context) {
    return context != null && context.isClientCellBlockSupported();
  }
Checks for the following pre-checks in order:
<ol>
<li>RegionServer is running</li>
<li>If authorization is enabled, then RPC caller has ADMIN permissions</li>
</ol>
@param requestName name of rpc request. Used in reporting failures to provide context.
@throws ServiceException If any of the above listed pre-check fails.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java