@Override
    public void visit(FileCopyGetMetaDataRequest fileCopyGetMetaDataRequest) {
      metrics.fileCopyGetMetadataRequestQueueTimeInMs.update(requestQueueTime);
      metrics.fileCopyGetMetadataRequestRate.mark();
      metrics.fileCopyGetMetadataProcessingTimeInMs.update(requestProcessingTime);
      responseQueueTimeHistogram = metrics.fileCopyGetMetadataResponseQueueTimeInMs;
      responseSendTimeHistogram = metrics.fileCopyGetMetadataSendTimeInMs;
      requestTotalTimeHistogram = metrics.fileCopyGetMetadataTotalTimeInMs;
      if (isRequestDropped) {
        metrics.fileCopyGetMetadataDroppedRate.mark();
        metrics.totalRequestDroppedRate.mark();
      }
    }
Used to update common metrics for the incoming request.
ambry-server/src/main/java/com/github/ambry/server/AmbryRequests.java