Thread Safety about protopromise HOT 2 CLOSED

After thinking about it a little more, even with the change of single-await-unless-retained pattern, the main thread event queue can remain in tact. This way every continuation would happen on the main thread, even though promises are being used in background threads. That would then lead to the next feature of execution context switching, where the user can determine whether the continuation occurs on the main thread or background thread.

from protopromise.

Alternatively, instead of using Retain and Release on a single promise object, we could do exactly what UniTask does and add a Preserve method that returns a new promise that can have any amount of callbacks added until Forget is called on it. This is probably safer than having to remember to call Release and Forget and worrying about any sort of calling order for those. Then Retain and Release can be removed/deprecated.

[Edit] Although, with this method, it would become unsafe to return a preserved promise (the caller could call Forget prematurely). Hmm... But then again, it's not fool-proof to return a retained promise, either, and this method is at least easier to get right I think.

from protopromise.