Request based availability distribution (#2423)
* WIP * availability distribution, still very wip. Work on the requesting side of things. * Some docs on what I intend to do. * Checkpoint of session cache implementation as I will likely replace it with something smarter. * More work, mostly on cache and getting things to type check. * Only derive MallocSizeOf and Debug for std. * availability-distribution: Cache feature complete. * Sketch out logic in `FetchTask` for actual fetching. - Compile fixes. - Cleanup. * Format cleanup. * More format fixes. * Almost feature complete `fetch_task`. Missing: - Check for cancel - Actual querying of peer ids. * Finish FetchTask so far. * Directly use AuthorityDiscoveryId in protocol and cache. * Resolve `AuthorityDiscoveryId` on sending requests. * Rework fetch_task - also make it impossible to check the wrong chunk index. - Export needed function in validator_discovery. * From<u32> implementation for `ValidatorIndex`. * Fixes and more integration work. * Make session cache proper lru cache. * Use proper lru cache. * Requester finished. * ProtocolState -> Requester Also make sure to not fetch our own chunk. * Cleanup + fixes. * Remove unused functions - FetchTask::is_finished - SessionCache::fetch_session_info * availability-distribution responding side. * Cleanup + Fixes. * More fixes. * More fixes. adder-collator is running! * Some docs. * Docs. * Fix reporting of bad guys. * Fix tests * Make all tests compile. * Fix test. * Cleanup + get rid of some warnings. * state -> requester * Mostly doc fixes. * Fix test suite. * Get rid of now redundant message types. * WIP * Rob's review remarks. * Fix test suite. * core.relay_parent -> leaf for session request. * Style fix. * Decrease request timeout. * Cleanup obsolete errors. * Metrics + don't fail on non fatal errors. * requester.rs -> requester/mod.rs * Panic on invalid BadValidator report. * Fix indentation. * Use typed default timeout constant. * Make channel size 0, as each sender gets one slot anyways. * Fix incorrect metrics initialization. * Fix build after merge. * More fixes. * Hopefully valid metrics names. * Better metrics names. * Some tests that already work. * Slightly better docs. * Some more tests. * Fix network bridge test.