33 Execution control library [exec]

33.9 Senders [exec.snd]

33.9.12 Sender adaptors [exec.adapt]

33.9.12.7 execution​::​schedule_from [exec.schedule.from]

The name schedule_from denotes a customization point object.
For some subexpression sndr, if decltype((​sndr)) does not satisfy sender, schedule_from(sndr) is ill-formed.
Otherwise, the expression schedule_from(sndr) is expression-equivalent to make-sender(schedule_from, {}, sndr).
[Note 1: 
schedule_from is used by schedulers to control how to transition off of their schedulers' associated execution contexts.
— end note]