A service to hide your answer to a question until a certain time. Are there any?

Question

Software and Internet Services

We are looking for a service (web) where you can ask your question and write your answer.
The question is visible to everyone, everyone can see the date of the entry (question + answer), you can see which user created it.
The answer is hidden until a certain time.
Everyone sees when the answer is open. (date and time)
At the appointed time, the answer becomes visible to everyone.
*not necessary. Users can submit their own answers (which are visible to everyone at once) or join other users' current answers. As soon as the appointed time comes, you can see who gave the correct answer.

What is it for: there is a need to give an answer to the question, which can be checked after a while, but so that the author of the question does not have the opportunity to change the answer. conditionally: the question is asked - intrigue for a week - then the answer is available.

Google could not tell, please tell people)
P.S. Perhaps such a service does not exist. Maybe someone will need this idea to implement.

Answer 1

The DokuWiki wiki engine and the Timer plugin . (Tested on version 2018-04-22 Greebo.)
(Add Discussion or Disqus plugin for comments .)