sdk: add support for listening to stream of live location updates

[torrybr]

Conversation related to this issue can be found here

This merge request adds subscribe_to_live_location_shares to the matrix_sdk::Room that allows clients to listen for beacon updates using a background task. The method provides an easy way to subscribe to live location sharing events within a room, handling event processing internally.

Follow-up tasks will include adding support for the event cache.

[stefanceriu]

Seems that the test aren't particularly happy with this PR. Can you please have a look?

[Hywan]

Thanks for the PR. I've left some feedback that can impact the global design of your patch.

[codecov]

Codecov Report

Attention: Patch coverage is 90.90909% with 2 lines in your changes missing coverage. Please review.

Project coverage is 85.02%. Comparing base (cefd5a2) to head (05c1172).

Files with missing lines	Patch %	Lines
crates/matrix-sdk/src/room/mod.rs	90.90%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4025      +/-   ##
==========================================
+ Coverage   85.00%   85.02%   +0.01%     
==========================================
  Files         274      274              
  Lines       29945    29964      +19     
==========================================
+ Hits        25456    25477      +21     
+ Misses       4489     4487       -2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[torrybr]

Updated with more comprehensive tests and ready for a re-review thanks

[Hywan]

I think we are almost done! Can you rebase your git history please?

[Hywan]

I've just merged #4253, and I believe it might interest you, or may your code a bit simpler. What do you think?

[Hywan]

There is still issues with the code (see comments). However, I suggest you to use #4253, where you can return your own subscriber, in which the produced stream can map the stream from EventHandlerSubscriber to generate a LiveLocationShare. See StreamExt::map.

[Hywan]

The caller has to take care of removing the event handler. With #4253, it becomes automatic/invisible for the caller.

[Hywan]

That's where you would have to call Client::remove_event_handler. You can use a EventHandlerDropGuard though, that would be this thing automatic too. If you use #4253, this is no longer required as you don't need to store a receiver and the event_handler_handle.

[torrybr]

I've just merged #4253, and I believe it might interest you, or may your code a bit simpler. What do you think?

Would you be open to merging this as-is using the existing .add_event_listener approach? I’d like to revisit it next week to refactor based on your new implementation, but it may take me some time to fully get up to speed with the new process. Given that this has been open for a while, merging it now would provide me a solid foundation for completing the rest of the location-sharing feature!

Recent commit makes use of the EventHandlerDropGuard as suggested and keeps it a little simpler without breaking it out.