private static AsyncRequestResponseHandler getAsyncRequestResponseHandler(int requestWorkers) throws IOException {
    RestRequestService restRequestService = new MockRestRequestService(verifiableProperties, router);
    RequestResponseHandlerMetrics metrics = new RequestResponseHandlerMetrics(new MetricRegistry());
    return new AsyncRequestResponseHandler(metrics, requestWorkers, restRequestService);
  }
Gets a new instance of {@link AsyncRequestResponseHandler}.
@param requestWorkers the number of request workers.
@return a new instance of {@link AsyncRequestResponseHandler}.
@throws IOException
ambry-rest/src/test/java/com/github/ambry/rest/AsyncRequestResponseHandlerTest.java