C API for interfacing with traces?

[danielocfb]

We could consider adding an API to blazesym-c for capturing traces emitted by the main crate. That could help with understanding of problems when even blaze_err is not sufficient.

I would think that most likely that will take a form similar to https://docs.rs/libbpf-rs/latest/libbpf_rs/fn.set_print.html, which allows users to set a function to be invoked for each "event".