Provide signals to notify [wait="ui_accept"] till the end and the functions to proceed (for network sync)

[RickyYCheng]

Is your feature request related to a problem? Please describe.
Multiplayer synchronization. The controlling peer should know when to broadcast the event, and other peers should have ability to proceed.

Describe the solution you'd like
The signals and functions to handle this.

Describe alternatives you've considered
Avoid using these api, for exmaple, using inline mutation to call custom functions so that we can handle multiplayer or other stuffs. This might be simpler but it is just drop the provided api.

Additional context
Non.