Question

You are optimizing a data structure that is massively read and very rarely written to. What is the best practice to improve the concurrency of this code?

```
type Cache struct {
	mu   sync.Mutex
	data map[string]string
}

func (c *Cache) Get(key string) string {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.data[key]
}
```

Accepted Answer

Replace sync.Mutex with sync.RWMutex and use RLock

Answer

Replace the lock with a dedicated read channel

Answer

Use sync.Map to avoid any manual locking

Answer

Use atomic.Value to store the entire map

Question from the Go test