fix(io): synchronizer can double lock in legacy Mode
Description
In legacy mode, the synchronizer can auto-lock.
Steps to reproduce
Run an application on windows, debug mode, which grabs and synchronizes images and positions. It might happen that the application freezes and locks.
Proposal
The issue is due to the legacy mode which fires a synchronization on a dedicated worker, and the data update which can fire a synchronize on its own woker.
This didn't happen before putting the legacy mode on its own worker.
This can be prevented by a return in the update in legacy mode.
Functional specifications
Applications should not freeze on synchronization.
Technical specifications
add a test for legacy mode in the update and return in this case. Synchronize should only be triggered from the timer .
Test plan
run module_synctest