Function std::intrinsics::atomic_xadd_rel

pub unsafe extern "rust-intrinsic" fn atomic_xadd_rel<T>(
    dst: *mut T, 
    src: T
) -> T where
    T: Copy, 

🔬 This is a nightly-only experimental API. (core_intrinsics)

intrinsics are unlikely to ever be stabilized, instead they should be used through stabilized interfaces in the rest of the standard library

加到当前值，返回前一个值。

通过将 Ordering::Release 作为 order 传递，可以通过 fetch_add 方法在 atomic 类型上使用此内联函数的稳定版本。 例如， AtomicIsize::fetch_add.