Explain the sync package and its primitives.

Sync Package Primitives: • Mutex: Mutual exclusion lock • RWMutex: Reader-writer lock • WaitGroup: Wait for goroutines • Once: Execute function once • Cond: Condition variables • Pool: Object pool • Map: Concurrent map Examples: // Mutex var mu sync.Mutex mu.Lock() defer mu.Unlock() // WaitGroup var wg sync.WaitGroup for i := 0; i < 10; i++ { wg.Add(1) go func(i int) { defer wg.Done() // work }(i) } wg.Wait() // Once var once sync.Once once.Do(func() { // initialization }) // Pool var pool = sync.Pool{ New: func() interface{} { return make([]byte, 1024) }, } buf := pool.Get().([]byte) defer pool.Put(buf)