在请求进行过程中修改golang Http Transport是否安全？

I have an application which rotates through proxies on a per request basis.

Currently I have some code which is:

func (mon *Monitor) MassUrlRetrieve(n int, url string) (respBytes []byte) {
    funnel := make(chan []byte)
    go ProductRetrieveTimeout(TIMEOUT_RETRIEVE_URL, funnel)
    for i := 0; i < n; i++ {
        go mon.WrapGetUrlToChannel(funnel, url)
    }
    return <- funnel
}

which basically sends off multiple requests and returns the first one to respond/ timeout if none respond in a timely manner.

In WrapGetUrlToChannel I create a new proxy url are assign it to mon's client.tr.Proxy.

My question is - is it safe to modify the transport of the client while requests are in flight? Or to be safe should I have a different transport and client for each proxy to make sure they do not interfere?

With the race detector it definitely showed that I shouldn't have been modifying the transport. In the end I decided on rotating *http.Transport around instead of proxies, and using unique clients when making concurrent requests.

Thanks to @Flimzy