@Override
  public void start() throws InstantiationException {
    logger.info("Starting PerfNioServer");
    loadCreatorThread.start();
    logger.info("Started PerfNioServer");
  }
Creates an instance of PerfNioServer.
@param perfConfig an instance of {@link PerfConfig} that determines behavior.
@param perfNioServerMetrics the {@link PerfNioServerMetrics} instance to use to record metrics.
@param restRequestHandler the instance of {@link RestRequestHandler} to use to handle requests.
ambry-tools/src/main/java/com/github/ambry/tools/perf/rest/PerfNioServer.java