How do I get detailed flamegraphs with the flame crate for code written using Rayon?

Question

I'm trying to get some performance metrics using the flame crate with code I've written using Rayon:

extern crate flame;

flame::start("TAG-A");
//Assume vec is a Vec<i32>
vec.par_iter_mut().filter(|a| a == 1).for_each(|b| func(b));
//func(b) operates on each i32 and sends some results to a channel
flame::end("TAG-A");
//More code but unrelated
flame::dump_stdout();

This works fine, but only gives information for the entire parallel iterator. I would like to get some more fine grained details on the function func.

I've tried adding a start/end within the function, but the runtime information is only available when I call flame::commit_thread() and then it seems to only print this to stdout. Ideally I'd like to print out the time spent without a given tag when I call dump at the end of my code.

Is there a way to dump tags from all threads? The documentation for flame isn't great.