Fix buffer issues with async IPC; add tests

[fselmo]

What was wrong?

Closes #3485

How was it fixed?

• Move to a readline() approach on the stream reader for IPC. The older implementation for the original IPC would read in chunks but this isn't ideal and, it turns out, opting for readline while allowing control of the buffer limit lends itself quite nicely to plucking well-formed responses from the socket.

Todo:

• [x] Clean up commit history / elaborate on commit message
• [x] Add or update documentation related to these changes
• [x] Add entry to the release notes

Cute Animal Picture

[raxhvl]

I wonder if chunks can arrive in arbitrary order. Also this thread discusses possible solutions.

[fselmo]

@raxhvl thanks for reporting. I believe this will be a more straightforward approach that can give control to the user to configure the read buffer limit if needs to be even larger than the default of 20MB. This should resolve your issues and I added a test to test this limit.