為什么我的 jsonrpc 方法返回空響應？type Args struct {  A, B int}type Response struct {  sum int  message string}type Arith intfunc (t *Arith) Add(r *http.Request, args *Args, reply *Response) error {  reply.sum = args.A + args.B  reply.message = "Do math"  // this does not work either  //*reply = Response{  //  sum : 12,  //  message : "Do math",  //}  return nil}要求：{"method":"Arith.Add","params":[{"A": 10, "B":2}], "id": 1}回復：{  "result": {},  "error": null,  "id": 1}但是，如果我將類型設置reply為*string，那么這將正常工作：*reply = "Responding with strings works"回復：{  "result": "Responding with strings works",  "error": null,  "id": 1}我正在使用http://www.gorillatoolkit.org/pkg/rpc。