private void clientMetricRegisterAndMark() {
      // Mark client metric
      String clientIP = RpcServer.getRemoteIp() != null ? RpcServer.getRemoteIp().toString() : null;
      if (clientIP == null || clientIP.isEmpty()) {
        return;
      }
      String clientRequestMeter = clientRequestMeterName(clientIP);
      clientMetricsLossyCounting.add(clientRequestMeter);
      registerAndMarkMeter(clientRequestMeter);
    }
Get regionId from Ops such as: get, put, delete.
@param op such as get, put or delete.
hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MetaTableMetrics.java