Receives the worker's replies.
Receives an uncaught error inside the worker (the worker then exits).
Receives the worker's exit.
Sends one request, moving the buffers in transferList to the worker.
Stops the worker thread.
Lets the process exit while the worker runs.
The encode worker as the host drives it: a
worker_threads.Workermatches it, and tests inject a fake. Member names mirror Node'sWorker.