Fix Kafka SmolRuntime hang, fixes #532

[Licenser]

Pull request

Fix hang on kafka producer

Description

This fixes a hang on the kafka producer when using queue.buffering.max.ms

Related

• Related Issues: fixes Investigate kafka egress issue #532

Checklist

• The RFC, if required, has been submitted and approved
• Any user-facing impact of the changes is reflected in docs.tremor.rs
• The code is tested (we currently can not test Kafka sinks/sources, manual tests will be done instead)
• Use of unsafe code is reasoned about in a comment

[codecov]

Codecov Report

Merging #558 into main will increase coverage by 0.39%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #558      +/-   ##
==========================================
+ Coverage   80.09%   80.49%   +0.39%     
==========================================
  Files         102      101       -1     
  Lines       13864    13770      -94     
==========================================
- Hits        11105    11084      -21     
+ Misses       2759     2686      -73     

Impacted Files	Coverage Δ
src/pipeline.rs	64.15% <100.00%> (+0.57%)	⬆️

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[mfelsche]

Mr. @Licenser can you enlighten me on why this fixes the hangs we've seen? I am more than curious.

[mfelsche]

I sneakily rebased on main

[mfelsche]

Verified on my machine. Good job!

[mfelsche]

❤️