fatal error: concurrent map read and map write
并发访问map是不安全的，会出现未定义行为，导致程序退出。所以如果希望在多协程中并发访问map，必须提供某种同步机制，一般情况下通过读写锁sync.RWMutex实现对map的并发访问控制，将map和sync.RWMutex封装一下，可以实现对map的安全并发访问，示例代码如下：
package main
import "sync"
type SafeMap struct {
sync.RWMutex
Map map[int]int
}
func main() {
safeMap := newSafeMap(10)
for i := 0; i < 100000; i++ {
go safeMap.writeMap(i, i)
go safeMap.readMap(i)
}
}
func newSafeMap(size int) *SafeMap {
sm := new(SafeMap)
sm.Map = make(map[int]int)
return sm
}
func (sm *SafeMap) readMap(key int) int {
sm.RLock()
value := sm.Map[key]
sm.RUnlock()
return value
}
func (sm *SafeMap) writeMap(key int, value int) {
sm.Lock()
sm.Map[key] = value
sm.Unlock()
}