Feature request: Stop-the-world mechanism

[playXE]

It would be nice to see some API to stop execution of all coroutines and then resuming them.

may::park_all();
/* do something */
may::unpark_all();

park_all and unpark_all could be executed in both non-coroutine and coroutine contexts.

Implementation

It's possible to have static PARK_ALL: AtomicBool and at yeach yield to scheduler context check PARK_ALL. But STW mechanism might also require to store coroutine or context that requested STW to resume this context.

[Xudong-Huang]

Doing the check in the scheduler is better. But this will hurt the overall performance. I don't think will support this feature in the master branch.