@Override
    public ResteasyAsynchronousResponse suspend(long millis) {
        return suspend(millis, TimeUnit.MILLISECONDS);
    }
Suspends client connection for asynchronous request processing.
@param millis a number of milliseconds to suspend client connection for.
@throws IllegalStateException if it was previously suspended.
resteasy/src/main/java/com/linecorp/armeria/server/resteasy/ResteasyAsynchronousExecutionContextImpl.java