rm go.work
cp go.mod.21 go.mod
go mod edit -godebug default=go1.20 -godebug asynctimerchan=0
go list -f '{{.Module.GoVersion}} {{.DefaultGODEBUG}}'
stdout panicnil=1
stdout asynctimerchan=0

# Go 1.21 go.work with godebug default=go1.20
cp go.work.21 go.work
go list -f '{{.Module.GoVersion}} {{.DefaultGODEBUG}}'
! stdout panicnil # go.work wins
stdout asynctimerchan=1 # go.work wins
go work edit -godebug default=go1.20 -godebug asynctimerchan=0

	if asynctimerchan.Value() == "1" {
		return nil
	}

	// Otherwise pass to runtime.
	// This handles asynctimerchan=0, which is the default Go 1.23 behavior,
	// as well as asynctimerchan=2, which is like asynctimerchan=1
	// but implemented entirely by the runtime.
	// The only reason to use asynctimerchan=2 is for debugging
	// a problem fixed by asynctimerchan=1: it enables the new

is in a module with a `go.mod` `go` line using Go 1.23.0 or later.
When Go 1.23 builds older programs, the old behaviors remain in effect.
The new [GODEBUG setting](/doc/godebug) [`asynctimerchan=1`](/pkg/time/#NewTimer)
can be used to revert back to asynchronous channel behaviors

// (Otherwise the runtime/metrics test will fail.)
//
// Note: After adding entries to this table, update the list in doc/godebug.md as well.
// (Otherwise the test in this package will fail.)
var All = []Info{
	{Name: "asynctimerchan", Package: "time", Changed: 23, Old: "1", Opaque: true},
	{Name: "execerrdot", Package: "os/exec"},
	{Name: "gocachehash", Package: "cmd/go"},
	{Name: "gocachetest", Package: "cmd/go"},