Thanks for letting me know your workflow. Yeah, that sounds unique!
Okay, so, extending the rendering delay would solve the issue. I’ll try it in the next version.
BTW, it made me think of trying the Rust Markdown parser by the same author of Micromark 
Yes, it will lose the parser extensibility but it will greatly improve the performance.
It is still in alpha though, a very interesting project. I’ll keep my eye on it.