Feature Proposal Description

The MemoryLock in locker.go is implemented so that allocated mutexes won't be collected by GC because it holds pointers to them even when it is not needed.
To be accurate:
It allocates new mutex for every idempotency key (and removes nowhere)

func (l *MemoryLock) Lock(key string) error {
	l.mu.Lock()
	mu, ok := l.keys[key]
	if !ok {
		mu = new(sync.Mutex)
		l.keys[key] = mu
	}
	l.mu.Unlock()

	mu.Lock()

	return nil
}

It might seem be okay until some calculations are made:
Imagine we have a server handling 1000 rps with idempotency keys. Every mutex holds 8 bytes.
So in 1 month of continuous work it will be 8 * 1000 * 60 * 60 * 24 * 30 = 20736000000 B = 19.312 GB

I propose key removal from map to allow GC collect unused Mutex. (Associated PR is created)

Alignment with Express API

N/A

HTTP RFC Standards Compliance

N/A

API Stability

N/A

Feature Examples

N/A

Checklist:

• I agree to follow Fiber's Code of Conduct.
• I have searched for existing issues that describe my proposal before opening this one.
• I understand that a proposal that does not meet these guidelines may be closed without explanation.