title: How to use model in query string for Retrofit 2?
body: <p>I am using a class model like below to hold the search data information, </p>
  
  <pre><code>data class SearchDataModel (
      var keyword: String? = "",
      var from: String? = "",
      var to: String? = "",
      var page: Int? = null,
      var sortby: String? = null,
      var orderby: String? = null,
      var itemsperpage: Int? = null
  )
  </code></pre>
  
  <p>For posting data we can use the call,</p>
  
  <pre><code>@POST("/data/save")
  fun saveData(@Body postData: PostDataModel)
  </code></pre>
  
  <p>How to achieve the same for query string something like the one below?</p>
  
  <pre><code>@GET("/data/search")
  fun searchData(@QueryString searchData: SearchDataModel)
  </code></pre>
  
  <p>I'm trying to prevent having lots of parameter in the function and have an optional query string parameter.</p>