golang sync.Map 是一个标准库中的一个并发安全的映射类型，特别适用于以下场景

package main

import (
"fmt"
"sync"
)

// A function that simulates a costly computation
func costlyComputation(key string) string {
// Simulate a costly computation
return "Result for " + key
}

func main() {
var cache sync.Map

// Function to get or compute a value
getOrCompute := func(key string) string {
	// Try to load the value from the cache
	if value, ok := cache.Load(key); ok {
		return value.(string)
	}

	// If the value is not in the cache, compute it
	result := costlyComputation(key)

	// Store the computed value in the cache
	cache.Store(key, result)

	return result
}

keys := []string{"a", "b", "a", "c", "b", "d"}

// Simulate multiple concurrent accesses to the cache
var wg sync.WaitGroup
for _, key := range keys {
	wg.Add(1)
	go func(k string) {
		defer wg.Done()
		result := getOrCompute(k)
		fmt.Printf("Key: %s, Result: %s\n", k, result)
	}(key)
}

wg.Wait()

}