Unhandled exceptions is a pretty normal one. You get kicked out to your app's topmost level and you lost your span. My wishlist to solve this (and I actually wrote an implementation in Python which leans heavily on reflection) is to be able to attach arbitrary data to stack frames and exceptions when they occur merge all the data top-down and send it up to your handler.
Signal handlers are another one and are a whole other beast simply because they're completely devoid of context.
They're icky (as language design / practices) to me precisely because you end up executing context-free code. But I'd probably also just start a new trace in my signal handler / exception handler tagged with "shrug"...
Signal handlers are another one and are a whole other beast simply because they're completely devoid of context.