Add get/put helpers for gzip writer pool

gzip.go

@@ -13,6 +13,18 @@ var gzWriterPool = sync.Pool{
 	},
 }
 
+func getGzipWriter(w io.Writer) *gzip.Writer {
+	gw := gzWriterPool.Get().(*gzip.Writer)
+	gw.Reset(w)
+	return gw
+}
+
+func putGzipWriter(gw *gzip.Writer) {
+	gw.Close()           // close if we haven't already
+	gw.Reset(io.Discard) // don't keep references
+	gzWriterPool.Put(gw)
+}
+
 // Verify we're implementing these interfaces at compile time.
 var (
 	_ http.ResponseWriter = &gzipResponseWriter{}

handler.go

@@ -318,14 +318,9 @@ func (h *Handler) writeResultTwirp(ctx context.Context, w http.ResponseWriter, s
 	// ResponseWriter.
 	if spec.ResponseCompression == CompressionGzip && w.Header().Get("Content-Encoding") == "" {
 		w.Header().Set("Content-Encoding", "gzip")
-		gw := gzWriterPool.Get().(*gzip.Writer)
-		gw.Reset(w)
+		gw := getGzipWriter(w)
+		defer putGzipWriter(gw)
 		w = &gzipResponseWriter{ResponseWriter: w, gw: gw}
-		defer func() {
-			gw.Close()           // close if we haven't already
-			gw.Reset(io.Discard) // don't keep references
-			gzWriterPool.Put(gw)
-		}()
 	}
 	if err != nil {
 		// Twirp always writes errors as JSON.