const runtime.gcBackgroundMode

4 uses

	runtime (current package)
		mgc.go#L1227: 	gcBackgroundMode gcMode = iota // concurrent GC and sweep
		mgc.go#L1335: 	mode := gcBackgroundMode
		mgc.go#L1396: 	if mode != gcBackgroundMode {
		mgc.go#L1458: 	if mode != gcBackgroundMode {