// SwapInt32 atomically stores new into *addr and returns the previous *addr value.
func SwapInt32(addr *int32, new int32) (old int32)
2.CompareAndSwapXxx系列:比较并交换;
// CompareAndSwapInt32 executes the compare-and-swap operation for an int32 value.
func CompareAndSwapInt32(addr *int32, old, new int32) (swapped bool)
3.AddXxx系列:加减;
// AddInt32 atomically adds delta to *addr and returns the new value.
func AddInt32(addr *int32, delta int32) (new int32)