一个简单的测试,不太懂这里为什么 goroutine 个数始终为2,主线程跟 goroutine 应该不能算在一起?不太懂
```go
package main
import (
"time"
"runtime"
)
func main(){
go func(){
for {
select {
case <-time.Tick(time.Second):
print(runtime.NumGoroutine())
}
}
}()
time.Sleep(time.Minute)
}
```