Seats concept

[dcz-self]

Hey, I'm working on improving Wayland input method support and wanted to use egui for showcase input method demos (because honestly, it's refreshingly simple).

The problem is, seats are a central concept in Wayland and I don't know how to hook it up to egui.

A seat is like another person sitting at the computer, doing an independent thing with a separate keyboard and pointer but sharing the applications. In principle, you can have multiple people using separate pointers at the same computer, using the same application, like drawing on a large table canvas. The applications get all the information to tell which pointer is which, so, for example, user A can click on the eraser tool button and it will not affect user B's current tool.

It could also be used for multiplayer games or remote desktops.

Input methods are also part of the seat system.

I have written an experimental integration with Smithay and I get the seat data attached to events, but then I'm stuck. egui::Event doesn't have a place for seats and I don't see anything else.

The concrete question is: how do I attach extra data in the integration and can receive this data around button.clicked()?