libz

I had the same problem，Can we do like this ? ``` func (g *gzipHandler) shouldCompress(req *http.Request) bool { if !strings.Contains(req.Header.Get("Accept-Encoding"), "gzip") || strings.Contains(req.Header.Get("Connection"), "Upgrade") || strings.Contains(req.Header.Get("Accept"), "text/event-stream") { return false...

@LawyZheng 👍 Looking forward to your PR. Maybe, I can help to review the code :)