Slide 21
Slide 21 text
https://github.com/Kotlin/KEEP/blob/master/proposals/coroutines.md#terminology
A coroutine builder [is] a function that takes some suspending
lambda as an argument, creates a coroutine, and, optionally,
gives access to its result in some form. For example, launch{},
future{}, and sequence{} [..] are coroutine builders. The
standard library provides primitive coroutine builders that are
used to define all other coroutine builders.