const runtime.gcBackgroundMode

4 uses

	runtime (current package)
		mgc.go#L581: 	gcBackgroundMode gcMode = iota // concurrent GC and sweep
		mgc.go#L693: 	mode := gcBackgroundMode
		mgc.go#L771: 	if mode != gcBackgroundMode {
		mgc.go#L838: 	if mode != gcBackgroundMode {