Tachyon's `StackTraceCollector` has two different ways to set `skip_idle`
I was looking at the code in Tachyon and I think I've found something that isn't quite right (or at least is misleading and needs to be documented?)
In the StackTraceCollector, it seems like self.skip_idle is set but never used, as every collect method gets another skip_idle parameter that they use in _iter_stacks (or their calls to parent class' methods).
Based on the code for e.g. live_collector, it seems like the pattern is to use the attribute, not a parameter.