code: public static HttpHandler getNext(HttpServerExchange httpServerExchange, HttpHandler next) throws Exception {
  		if (next != null) {
  			return next;
  		}
  		return getNext(httpServerExchange);
  	}
docs: Returns the instance of the next handler, or the given next param if it's not
  null.
  
  @param httpServerExchange
  The current requests server exchange.
  @param next
  If not null, return this.
  @return The next handler in the chain, or next if it's not null.
  @throws Exception exception