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# Description of Changes This reapplies the patch from #3704, and fixes the issues that were causing it to deadlock. The reason it was deadlocking was that it allowed for the following sequence of events: * `SchedulerActor::handle_queued()` begins mutable tx * `ModuleHost::disconnect_client()` submits call to `call_reducer(tx: None)` * scheduler submits call to `call_reducer(tx: Some)` * `WasmModuleInstance::disconnect_client` now has to try to take tx lock, but the scheduler's call_reducer already holds it and is behind it in the queue So, I moved most of the logic from `handle_queued` back to being executed in the module worker thread, but kept the code in `scheduler.rs` so that it can all be reasoned about locally. Fixes #3645. Should I uncomment the implementation of `ExportFunctionForScheduledTable for F: Procedure` now? # Expected complexity level and risk 2 - there's a chance that this patch hasn't fully fixed the deadlock issue from #3704, but I'm quite confident. # Testing - [x] Manually verified that deadlock no longer occurs - previously, `while true; do python -m smoketests schedule_reducer -k test_scheduled_table_subscription; done` would freeze up in only 2 or 3 iterations, but now it can run for 10 minutes without issues.