A5.21 A multithreaded web server wishes to keep track of the number of requests it services (known as hits). Consider the two following strategies to prevent a race condition on the variable hits. The first strategy is to use a basic mutex lock when updating hits: int hits; mutex_lock hit_lock; hit_lock.acquire(); hits++; hit_lock.release(); A second strategy is to use an atomic integer: atomic_t hits; atomic_inc(&hits); Explain which of these two strategies is more efficient.