Have you used the pessimistic locking mechanism in your projects?

Yes, in Go projects I have used pessimistic locking when it was necessary to guarantee exclusive access to a resource.

Pessimistic locking assumes that when working with shared data, access is blocked for other goroutines until the operation is complete to avoid conflicts.

In Go, this is usually done using:

• sync.Mutex — a mutex for mutual exclusion.
• sync.RWMutex — to separate locks for reading and writing.

Example of using sync.Mutex:

var mu sync.Mutex
var counter int

func increment() {
    mu.Lock()
    defer mu.Unlock()
    counter++
}

This approach helps prevent data races but can reduce parallelism, so it is important to use locks judiciously.