Description

This PR reverts #4895 and fixes a few things by re-introducing the ack flag but also making sure the ack flag gets reset under unordered acks as well as resetting the ack flag when a second has passed. This prevents the flag from somehow putting clients in an infinite state.

This has dramatically fixed unnecessary resends and fixed issues observed on PEQ.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Testing

Extensive testing and hours with a 100 boxer on PEQ.

Checklist

• I have tested my changes
• I have performed a self-review of my code. Ensuring variables, functions and methods are named in a human-readable way, comments are added only where naming of variables, functions and methods can't give enough context.
• I own the changes of my code and take responsibility for the potential issues that occur