[FL-3833] Furi: event loop

[skotopes]

What's new

• Furi: event loop
• Furi: message queue event loop integration
• ViewDispatcher: multiple queue + event loop

Implemented

• EventLoop foundation: level based In/Out.
• Message Queue integration
• Lazy ticks integration
• Postponed events
• Obect to Epoll abstraction layer

Missing

• Edge events
• One Shot and other less common flags
• Priorities
• Priority inversion

Verification

• Full set of tests

Checklist (For Reviewer)

• [x] PR has description of feature/bug or link to Confluence/Jira task
• [x] Description contains actions to verify feature/bugfix
• [x] I've built this code, uploaded it to the device and verified feature/bugfix

[github-actions[bot]]

Compiled f7 firmware for commit cc0f7e11:

• 📦 Update package
• 📥 DFU file
• ☁️ Web/App updater
• 📊 Size report

[CookiePLMonster]

Can epoll events add/remove message queues to/from that epoll or is it not allowed?

[skotopes]

@CookiePLMonster yes, that should be possible. However I have not yet covered it with tests.

[CookiePLMonster]

@skotopes the reason I'm asking because literally the first thing that came to mind when I studied this PR was "Does this mean the scenes in a scene manager can now easily have their own message queues if needed?" which naturally means queues would be added and removed from a view dispatcher call (I think?).

[skotopes]

@CookiePLMonster yes. That was original intent of this PR: one event loop to rule them all.

[CookiePLMonster]

Now that the PR is out of draft, question about the usage - if furi_event_loop_message_queue_subscribe mandates the event loop must be idle for subscriptions/unsubscriptions to work, how does one add/remove message queues during the lifetime of the event loop? For example when switching scenes.

[skotopes]

@CookiePLMonster this feature coming in next release. This PR is a first part of many )