[smueller1234]

Zeromq will have changed a lot since then, but some time in the 2010s, I prototyped a system using it (which was going to be a major production system in a large tech company) and had weird unexpected blocking issues with it. To debug, I sat down to read a bunch of the zeromq code, just to realize that it was using assert() to handle wire protocol errors (unrelated to the blocking bug).

I've never dropped a piece of software as quickly as that.

[rcxdude]

More or less my experience as well. Asserting on bad user configuration, asserting on OS errors that weren't in a particular list. I followed their recommendation of having a "small, simple, reliable" broker and it kept crashing on asserts in the library at the worst times.