code: @Override
    public <T, U extends T> AutoCloseable registerHandler(
        final Class<U> messageType, final EventHandler<RemoteMessage<T>> theHandler) {
  
      if (LOG.isLoggable(Level.FINE)) {
        LOG.log(Level.FINE, "RemoteManager: {0} messageType: {1} handler: {2}", new Object[] {
            this.name, messageType.getCanonicalName(), theHandler.getClass().getCanonicalName()});
      }
  
      return this.handlerContainer.registerHandler(messageType, theHandler);
    }
docs: Registers an event handler for a message type and returns a subscription.