message: check AtomicU64 with target_has_atomic, fixed
diff: use std::sync::atomic::Ordering;
  -#[cfg(not(any(target_arch = "mips", target_arch = "powerpc")))]
  +#[cfg(target_has_atomic = "64")]
  type FlowCounter = std::sync::atomic::AtomicU64;
  -#[cfg(any(target_arch = "mips", target_arch = "powerpc"))]
  +#[cfg(not(target_has_atomic = "64"))]
  type FlowCounter = std::sync::atomic::AtomicU32;
  /// Connection flow statistic
  