@Override
  public SocketNetworkClient getNetworkClient() throws IOException {
    MockSelector selector = new MockSelector(serverLayout, state, time, networkConfig);
    return new SocketNetworkClient(selector, networkConfig, new NetworkMetrics(new MetricRegistry()), maxPortsPlainText,
        maxPortsSsl, checkoutTimeoutMs, time);
  }
Return a {@link SocketNetworkClient} instantiated with a {@link MockSelector}
@return the constructed {@link SocketNetworkClient}
@throws IOException if the selector could not be constructed.
ambry-router/src/test/java/com/github/ambry/router/MockNetworkClientFactory.java