func ClearMask(bits *int64, mask int64) {
	*bits &^= mask
}
ClearMask clears all of the bits in the mask
package bitflag
import "sync/atomic"
func SetMask(bits *int64, mask int64) {
	*bits |= mask
}
func SetMaskAtomic(bits *int64, mask int64) {
	for {
		cr := atomic.LoadInt64(bits)
		nw := cr | mask
		if atomic.CompareAndSwapInt64(bits, cr, nw) {
			break
		}
	}
}