Fix for #1153 - Semaphore disposed before discarded tasks have finished

[ashneilson]

Proposed Changes

Catch an ObjectDisposedException when attempting to Release the _limiter Semaphore after the WorkPool has been stopped.

Types of Changes

• Bug fix (non-breaking change which fixes issue Regression in 6.2.3: Semaphore Disposed Exception thrown in AsyncConsumerWorkService #1153)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• Documentation improvements (corrections, new content, etc)
• Cosmetic change (whitespace, formatting, etc)

Checklist

• I have read the CONTRIBUTING.md document
• I have signed the CA (see https://cla.pivotal.io/sign/rabbitmq)
• All tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in related repositories

[michaelklishin]

Thank you!

[lukebakken]

I will see if this needs to be ported to the other branches. 6.2.4 release will happen today or tomorrow.

[ashneilson]

Wow this is a fantastic response! Thank you both

[lukebakken]

This does not appear to apply to the main branch. Checking 7.x next.