This library provides a sync.Cond that has a WaitContext() method.
WaitContext(context.Context) waits for either the condvar to wake it, or the context to be cancelled.
It returns nil if the condvar woke it, or ctx.Err() if the context was cancelled.
contextcond is slower than sync.Cond, so you should only use it if you need WaitContext().
$ go test -bench .
goos: linux
goarch: amd64
pkg: github.com/Jille/contextcond
cpu: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
BenchmarkCond1-8 560541 1968 ns/op
BenchmarkCond2-8 196060 7049 ns/op
BenchmarkCond4-8 95750 12685 ns/op
BenchmarkCond8-8 49628 25710 ns/op
BenchmarkCond16-8 34155 37504 ns/op
BenchmarkCond32-8 14602 82923 ns/op
Compared to sync.Cond:
$ go test -bench . /usr/lib/go-1.19/src/sync/cond_test.go
goos: linux
goarch: amd64
cpu: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
BenchmarkCond1-8 1509849 782.1 ns/op
BenchmarkCond2-8 447687 2589 ns/op
BenchmarkCond4-8 251739 5226 ns/op
BenchmarkCond8-8 118968 11194 ns/op
BenchmarkCond16-8 44931 24098 ns/op
BenchmarkCond32-8 28124 40405 ns/op