这 API 设计的很有趣，跟函数名有异曲同工之妙

Ymx1ZW1hcmtAMTI2LmNvbQo=
谢谢

@bwangel
```go
package main

import "fmt"

func gen(v string, times int) <-chan string {
ch := make(chan string)
go func() {
defer close(ch)
for i := 0; i < times; i++ {
ch <- v
}
}()
return ch
}

func fanIn(times int, inputs []<-chan string) <-chan string {
ch := make(chan string)
go func() {
defer close(ch)
for i := 0; i < times; i++ {
for _, input := range inputs {
v := <-input
ch <- v
}
}
}()
return ch
}

func main() {
times := 10
inputs := make([]<-chan string, 0, 3)
for _, K := range []string{"A", "B", "C"} {
inputs = append(inputs, gen(K, times))
}
for i := range fanIn(times, inputs) {
fmt.Println(i)
}
}

```

可以多开个 channel，避免加锁
func fanIn() <-chan string{
inCh := make(chan string)
go func() {
defer close(inCh)
for i := 0; i < 10; i++{
inCh <- aCh
inCh <- bCh
inCh <- cCh
}
}()
return inCh
}

需要将交通卡设置为默认卡
之前也是这样失败，改成默认卡就好了