Mojolicious is a web development toolkit and framework built around an event loop. That has many performance and scalability advantages, but can also make debugging slow code a bit of a challenge.

Especially in big projects like openQA, where Devel::NYTProf can be a bit tricky to use, it would be nice to have more built-in diagnostics tools at the event reactor level. Mojo::UserAgent already has very good diagnostics features with MOJO_USERAGENT_DEBUG, and we should be able to do something similar for Mojo::IOLoop.