Performance improvements when rendering

- Fast path for JSON, XML and plain text rendering

render/data.go

@@ -0,0 +1,20 @@
+package render
+
+import "net/http"
+
+type dataRender struct{}
+
+func (_ dataRender) Render(w http.ResponseWriter, code int, data ...interface{}) error {
+	contentType := data[0].(string)
+	bytes := data[1].([]byte)
+	WriteData(w, code, contentType, bytes)
+	return nil
+}
+
+func WriteData(w http.ResponseWriter, code int, contentType string, data []byte) {
+	if len(contentType) > 0 {
+		w.Header().Set("Content-Type", contentType)
+	}
+	w.WriteHeader(code)
+	w.Write(data)
+}