Cancelable event

[Bafbi]

Describe the problem related to your feature request.

With the bukkit api something that's really often used is the ability to cancel events and that also reverse the action for the client.

Currently in Valence events are sent at the same time that the packet is treated by the plugin, so it's not possible to cancel the event and reverse it manually make no sense neither cause it has already been treated by the plugin

What solution would you like?

I think we should separate the event from the plugin code.
Make the eventWriter run firstly then the user can handle the event and cancel it if he wants, finally the plugin runs his code and reverse the client if it has been canceled or treat it if not.

What alternative(s) have you considered?

Open to suggestions

[pepperoni21]

I don't think bevy allows to mutate the event and then fetch it once listeners have been triggered

[Bafbi]

No, that's why I'm creating a new event system.