Function waiter

test/bthread_butex_unittest.cpp:123–136

};

void* waiter(void* arg) {
    WaiterArg * wa = (WaiterArg*)arg;
    const long t1 = butil::gettimeofday_us();
    const int rc = bthread::butex_wait(
        wa->butex, wa->expected_value, wa->ptimeout);
    const long t2 = butil::gettimeofday_us();
    if (rc == 0) {
        EXPECT_EQ(wa->expected_result, 0) << bthread_self();
    } else {
        EXPECT_EQ(wa->expected_result, errno) << bthread_self();
    }
    LOG(INFO) << "after wait, time=" << (t2-t1) << "us";
    return NULL;
}

TEST(ButexTest, sanity) {
    const size_t N = 5;