Does Builder::on_thread_park on current thread scheduler guarantee to execute the function in main thread?

[ultimaweapon]

I need to do some works during the executor is idle but the problem is the object I need to pass to Builder::on_thread_park does not Send and Sync.

[Darksonn]

It's guaranteed that on_thread_park only runs on threads where you called Runtime::block_on. So you control where the callback runs.

(It does not run on Handle::block_on threads.)

[ultimaweapon]

Thanks!