homingway/hickwall: newcore/fanout.go; 23 LoC

Found a possible issue in [homingway/hickwall](https://www.github.com/homingway/hickwall) at [newcore/fanout.go](https://github.com/homingway/hickwall/blob/2e1063aa3cf5eeee29adc3a494c3633ec8fc4e0c/newcore/fanout.go#L118-L140)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first
issue it finds, so please do not limit your consideration to the contents of the below message.

> range-loop variable bk used in defer or goroutine at line 126

[Click here to see the code in its original context.](https://github.com/homingway/hickwall/blob/2e1063aa3cf5eeee29adc3a494c3633ec8fc4e0c/newcore/fanout.go#L118-L140)

Click here to show the 23 line(s) of Go which triggered the analyzer.

```go
for idx, bk := range f.bks {
// closing consuming of each backend
consuming_errc := make(chan error)
f.closing_list[idx] <- consuming_errc
<-consuming_errc

// close backend.
go func() {
consuming_errc <- bk.Close()
}()
timeout := time.After(time.Duration(1) * time.Second)
wait_bk_close:
for {
select {
case <-consuming_errc:
break wait_bk_close
case <-timeout:
logging.Errorf("backend(%s) is blocking the fanout closing process!\n", bk.Name())
break wait_bk_close
}
}

}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: 2e1063aa3cf5eeee29adc3a494c3633ec8fc4e0c