rust project-5: SharedQueueThreadPool doesn't exit when pool destroyed

Bug Report

1. What did you do?

Inspecting the source code in SharedQueueThreadPool

2. What did you expect to see?

The loop of function fn run_task(rx: TaskReceiver) should break when rx.0.recv returns an error and return from the function.

3. What did you see instead?

It logs an error message and goes on looping