title: Gson ignore field on serialization under condition
body: <p>I have an object </p>
  
  <pre><code>data class FileInformation(
      @SerializedName("filename")
      val fileName: String,
      @SerializedName("filesize")
      val fileSize: Long,
      @SerializedName("filedate")
      val fileDate: String,
  
      var status: Int = FILE_PENDING)
  </code></pre>
  
  <p>There are times that i want to serialize the above class WITH the status field but other times WITHOUT the status field. How can i do that??</p>