> If you look at iteration, it actually is about concurrency. You’ve got two “threads” of behavior: one that’s generating values and one that’s consuming them. You need to run these two threads together and coordinate them. That is concurrency. We’re just so used to it, that we don’t think of it that way.

#quote #PL | 关于推式和拉式迭代器

https://journal.stuffwithstuff.com/2013/01/13/iteration-inside-and-out