const runtime.gcBackgroundMode

4 uses

	runtime (current package)
		mgc.go#L671: 	gcBackgroundMode gcMode = iota // concurrent GC and sweep
		mgc.go#L783: 	mode := gcBackgroundMode
		mgc.go#L889: 	if mode != gcBackgroundMode {
		mgc.go#L965: 	if mode != gcBackgroundMode {