rust / LEVEL 4
THEORY / RETRIEVAL
An unbounded channel turns overload into memory growth and stale work. A bounded channel makes the maximum waiting set explicit. Non-blocking admission can reject excess jobs immediately, while blocking send applies producer backpressure; the caller must choose that behavior deliberately.
A receiver iterator ends only after every sender is dropped and the accepted queue is drained. Joining the worker while any sender clone remains live can wait forever. Consuming shutdown should close admission first, then join and return the processed evidence.
JoinHandle::join returns the panic payload instead of forcing the joining thread to panic. A service boundary can translate that outcome into a typed error, preserving a deterministic caller contract without pretending that partially completed external effects were rolled back.
CHECKPOINT
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02 / DEBUGGING
Repair BoundedWorker without changing its public API. Capacity zero must fail before spawning. try_submit must never block, must preserve the rejected job in Full or Closed, and must admit at most capacity waiting jobs. One worker processes accepted jobs exactly once in order. shutdown must drop the last sender before join, drain accepted jobs and translate panic into WorkerPanicked.
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