Sentry-arroyo

Various fixes & improvements

- Revert "feat: add more item size stats to multiprocessing (and metrics refactor) (235)" (240) by untitaker
- fix(multiprocessing): More performant backpressure [INC-378] (238) by untitaker
- fix(multiprocessing): Honor join() timeout even if processing pool is overloaded [INC-378] (237) by untitaker
- docs: Minor readability details (236) by kamilogorek
- feat: add more item size stats to multiprocessing (and metrics refactor) (235) by untitaker

Various fixes & improvements

- fix: Distinguish between backpressure and output overflow (234) by untitaker

Various fixes & improvements

- perf(dlq): Improve performance when there are many invalid messages (233) by lynnagara

Various fixes & improvements

- chore(processor): More logs for shutdown sequences (230) by nikhars
- fix: Remove flaky test (232) by untitaker
- fix: Do not log error when consumer is already crashing (228) by untitaker

Various fixes & improvements

- fix(run_task_with_multiprocessing): Do not attempt to skip over invalid messages (231) by untitaker

Various fixes & improvements

- chore(processor): Add more logging (229) by nikhars
- doc: Document how backpressure currently works (227) by untitaker
- ref: Remove extraneous codecs from arroyo (219) by untitaker