Method fetch_or

src/butil/atomicops.h:307–307

    T fetch_sub(T v, memory_order o) { return ref().fetch_sub(v, o); }
    T fetch_and(T v, memory_order o) { return ref().fetch_and(v, o); }
    T fetch_or(T v, memory_order o) { return ref().fetch_or(v, o); }
    T fetch_xor(T v, memory_order o) { return ref().fetch_xor(v, o); }
    static_atomic& operator=(T v) {
        store(v, memory_order_seq_cst);