What's the reasoning here? What are the limitations of the built-in retry?

A rule of thumb that I try to follow for comments:
- always describe _what_
  - do this at the file/module, class, and function/method level
  - you can avoid doing it for functions/methods when they're very short or obvious
- describe _why_ if not obvious
  - which is most of the time
  - more important than _what_ and _how_ since you can eventually figure those out from reading the code
- only describe _how_ when complicated