A few of these are copied from the memory model doc.
Many are entirely new, following discussion on #47141.
See https://research.swtch.com/gomm for background.
The rule we are establishing is that each type that is meant
to help synchronize a Go program should document its
happens-before guarantees.
For #50859.
Change-Id: I947c40639b263abe67499fa74f68711a97873a39
Reviewed-on: https://go-review.googlesource.com/c/go/+/381316
Auto-Submit: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Alan Donovan <adonovan@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Roland Shoemaker <roland@golang.org>