`Task` - delete from public API or add an example?

[pubrrr]

What problem does this solve or what need does it fill?

From the discussion in #4102: Should bevy keep Task in it's public API?

What solution would you like?

Is there a use case where one needs to use Task instead of PollableTask? Currently, there are two examples on async tasks:

• one for the usage of PollableTask: A task that returns one result that can be polled on, using bevy's TaskPool.
• one using custom threads and channels: Arbitrary async tasks, not using bevy's async functionality at all.

Either there is a use case for Task -> add an example.
Or there is no use case -> remove Task from the public API, the user should then either use PollableTask or custom threads.

[maniwani]

If you make Task non-pub, just take it's name. PollableTask is too much typing.

But I also think that "never block, only poll" or "either poll or use OS threads" are silly positions. That just sounds like something that'll frustrate someone in the next jam.

Wanting to wait for an async op to complete in the middle of a system isn't unreasonable, so, if we can, IMO we should give people easy ways to poll and block using the same task handle type.