Fixes https://github.com/vector-im/riot-web/issues/14411
The act of setting/changing the algorithm was causing the update function to be marked, meaning we wouldn't trigger an update until something else happened later. To get around this, and still support internal functions spamming calls without multiple updates, we simply move the guts to an internalized function and make the public interface do a trigger.
this way we have a flexbox layout in the resizer with:
- the resize handle (fixed)
- the show more/less button, if any (fixed)
- the list of tiles (grabbing whatever is left)
For https://github.com/vector-im/riot-web/issues/14035
**This option is not recommended as it completely obliterates all chances of being able to support someone with a broken room list. It is intended for specific testing scenarios only.**
The room list does a hefty amount of work, so instead of blocking the event loop with a `/sync` request and a bunch of room updates (as we can get multiple per sync) we can instead run it over several smaller tasks. The smaller tasks help the event loop do other things between our tasks, ensuring we don't inadvertently block the UI from rendering too slowly.
On my account and machine, this cuts the time to render in half (~30ms, down from ~60ms) .
The core of this is in the MarkedExecution class, with the remainder of the commit ensuring that the right marks and triggers are in place to do the firing.
Because everything is async/await and run through the RoomListStore, we don't have to worry about self-fed updates in the algorithm classes. This also means we have to trigger pretty much all the time.
Changes to tag ordering / list sorting get hit through two paths, so we mark before we do a bulk update and otherwise assume the call is coming in from outside.
Known issues:
* Causes scroll jumps when the button gets added to DOM
* Resize handle is invisible when there's a show more button
TODO:
* Clean up comments
* Clean up useless code (all the padding stuff isn't needed)
