code: public final TcpServer doOnBind(Consumer<? super ServerBootstrap> doOnBind) {
  		Objects.requireNonNull(doOnBind, "doOnBind");
  		return new TcpServerDoOn(this, doOnBind, null, null);
  
  	}
docs: Setups a callback called when {@link io.netty.channel.ServerChannel} is about to
  bind.
  
  @param doOnBind a consumer observing server start event
  
  @return a new {@link TcpServer}