@UnstableApi
    public ServerBuilder serviceWorkerGroup(EventLoopGroup serviceWorkerGroup, boolean shutdownOnStop) {
        virtualHostTemplate.serviceWorkerGroup(serviceWorkerGroup, shutdownOnStop);
        return this;
    }
Sets the worker {@link EventLoopGroup} which is responsible for running
{@link Service#serve(ServiceRequestContext, Request)}.
If not set, the value set via {@linkplain #workerGroup(EventLoopGroup, boolean)}
or {@linkplain #workerGroup(int)} is used.

@param shutdownOnStop whether to shut down the worker {@link EventLoopGroup}
                      when the {@link Server} stops
core/src/main/java/com/linecorp/armeria/server/ServerBuilder.java