Catch all exceptions in HeartbeatWriteTimerCallback and HeartbeatReadTimerCallback to avoid crash

[klettier]

Proposed Changes

My application crashed with the following stack trace

Checking the code I discovered that HeartbeatReadTimerCallback has async void signature that may crash the application in case of exception

I'm using

• client version 7.1.1
• server version 4.0.9
• dotnet 8

I also took the opportunity to modify HeartbeatWriteTimerCallback even if it was already catching exceptions.
I didn't found other async void in the code.

Types of Changes

• Bug fix (non-breaking change which fixes issue #NNNN)
• 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

Further Comments