void handle(RestRequest restRequest, RestResponseChannel restResponseChannel,
      Callback<ReadableStreamChannel> callback) {
    RestRequestMetrics requestMetrics =
        metrics.getPeersMetricsGroup.getRestRequestMetrics(restRequest.isSslUsed(), false);
    restRequest.getMetricsTracker().injectMetrics(requestMetrics);
    securityService.processRequest(restRequest,
        new SecurityProcessRequestCallback(restRequest, restResponseChannel, callback));
  }
Handles a request for peers of a given datanode. Expects the arguments to have {@link #NAME_QUERY_PARAM} and
{@link #PORT_QUERY_PARAM}. Returns the peers as a JSON with the field {@link #PEERS_FIELD_NAME} whose value is a
JSON array of objects with fields {@link #NAME_QUERY_PARAM} and {@link #PORT_QUERY_PARAM}.
@param restRequest the {@link RestRequest} that contains the request parameters.
@param restResponseChannel the {@link RestResponseChannel} where headers should be set.
@param callback the {@link Callback} to invoke when the response {@link ReadableStreamChannel} is ready (or if
                there is an exception).
ambry-frontend/src/main/java/com/github/ambry/frontend/GetPeersHandler.java