title: using map[string]interface{} :
body: <p>Given the following code:</p>
  
  <pre><code>type Message struct {
      Params map[string]interface{} `json:"parameters"`
      Result interface{}            `json:"result"`
  }
  
  func (h Handler) Product(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
  
      msg := &amp;Message{
          Action: "get_products",
          Params: {
              "id1": val1,
              "id2": val2,
          },
      }
       h.route(msg)
  
  }
  </code></pre>
  
  <p>The idea is to be able to send a block of an unknown amount id1 => val1, id2 =>val2 ... to h.route.</p>
  
  <p>it gives me this error:</p>
  
  <blockquote>
    <p>missing type in composite literal</p>
  </blockquote>