[QUESTION] How to implement a custom VOID element?

[rockingdice]

I want to implement a <wiki data="12345">, it's a void element, without an end tag </wiki>. I tried TagExtension, it can show the first widget, but the contents after it are all disappeared. I think it's treated like a normal element with an end tag, so everything inside the <wiki></wiki> will not shown because i didn't process them. But the core issue is , there should not be a </wiki> at all. the <wiki> tag itself is only a widget to show without any other things. How to implement that?