// We should have a series of filled and emptyOne cells, followed by
	// a series of emptyRest cells.
	h := *(**hmap)(unsafe.Pointer(&m))
	i := any(m)
	t := *(**maptype)(unsafe.Pointer(&i))

	for x := 0; x < 1<<h.B; x++ {
		b0 := (*bmap)(add(h.buckets, uintptr(x)*uintptr(t.BucketSize)))
		n := 0
		for b := b0; b != nil; b = b.overflow(t) {