Go疑问-1

package main

import (
    "fmt"
)

func main() {
    var numbers = make([]int, 0)
    ch := make(chan int, 100)
    count := 10
    for i := 0; i < count; i++ {
        go func() {
            fmt.Printf("i = %d\n",i)
            ch <- i
        }()
    }

    visit := 0
    for num := range ch {
        fmt.Printf("num = %d\n",num)
        numbers = append(numbers, num)
        visit++
        if visit == count {
            break
        }
    }
    fmt.Println(len(numbers))
}

输出：

i = 2
i = 7
i = 7
i = 7
i = 8
i = 10
num = 7
i = 10
num = 7
num = 7
num = 8
num = 10
i = 10
num = 10
num = 10
i = 3
i = 3
num = 10
num = 10
num = 10
10

但：如果把goroutine的匿名函数改成常规有名函数，就输出正常，何故？闭包？