browser return application/octet-stream (0 byte) when url TrailingSlash

[tablecell]

package main

import (
	"bytes"
 	"github.com/aofei/air"
 )

var a = air.Default

func identicon(req *air.Request, res *air.Response) error {
 	return res.Write(bytes.NewReader(req.ParamValue("Name").Bytes()))
}
func main() {
	a.DebugMode = true
 
	a.GET("/identicons/:Name", identicon)
	a.Serve() //8080 
}

visit http://localhost:8080/identicons/