code: public void setServerCustomizers(
  			Collection<? extends NettyServerCustomizer> serverCustomizers) {
  		Assert.notNull(serverCustomizers, "ServerCustomizers must not be null");
  		this.serverCustomizers = new ArrayList<>(serverCustomizers);
  	}
docs: Set {@link NettyServerCustomizer}s that should be applied to the Netty server
  builder. Calling this method will replace any existing customizers.
  @param serverCustomizers the customizers to set