fix: allow ResponseReader.Reader to be wrapped by transcoders

fixes -minify errors

proxy/proxy.go

@@ -69,7 +69,7 @@ func (p *Proxy) handle(w http.ResponseWriter, r *http.Request) error {
 	rw := newResponseWriter(w)
 	rr := newResponseReader(resp)
 	err = p.proxyResponse(rw, rr)
-	read := rr.Count()
+	read := rr.counter.Count()
 	written := rw.rw.Count()
 	log.Printf("transcoded: %d -> %d (%3.1f%%)", read, written, float64(written)/float64(read)*100)
 	atomic.AddUint64(&p.ReadCount, read)

proxy/response.go

@@ -9,14 +9,17 @@ import (
 )
 
 type ResponseReader struct {
-	datacounter.ReaderCounter
-	r *http.Response
+	io.Reader
+	counter *datacounter.ReaderCounter
+	r       *http.Response
 }
 
 func newResponseReader(r *http.Response) *ResponseReader {
+	counter := datacounter.NewReaderCounter(r.Body)
 	return &ResponseReader{
-		ReaderCounter: *datacounter.NewReaderCounter(r.Body),
-		r:             r,
+		Reader:  counter,
+		counter: counter,
+		r:       r,
 	}
 }