code: public static void finalizeHandler(ServerBootstrap b, ChannelOperations.OnSetup
  			opsFactory, ConnectionObserver childListener) {
  		Objects.requireNonNull(b, "bootstrap");
  		Objects.requireNonNull(opsFactory, "ops");
  		Objects.requireNonNull(childListener, "childListener");
  
  		BootstrapPipelineHandler pipeline = null;
  		ChannelHandler handler = b.config().childHandler();
  		if (handler instanceof BootstrapPipelineHandler) {
  			pipeline = (BootstrapPipelineHandler) handler;
  		}
  
  		b.childHandler(new BootstrapInitializerHandler(pipeline, opsFactory, childListener));
  	}
docs: Finalize a server bootstrap pipeline configuration by turning it into a {@link
  ChannelInitializer} to safely initialize each child channel.
  
  @param b a server bootstrap
  @param opsFactory an operation factory
  @param childListener a connection observer