title: Method cannot be marked @objc because the type of the parameter 2 cannot be represented in Objective-C
body: <p>I implemented a delegate in which all functions are optional, but I needed to make changes to one of the functions, namely add a second parameter, but I got this error <strong>"Method cannot be marked @objc because the type of the parameter 2 cannot be represented in Objective-C"</strong>. How can I fix this? Thank you.</p>
  
  <pre><code>@objc protocol ConversationDelegate: class {
  
      @objc optional func didUpdateConversation(_ conversation: ChatUserPersonalConversationModel, type: ChatGeneralManager.ConversationUpdateType) // **error here** 
      @objc optional func didDownloadedAllConversation()
      @objc optional func didDeleteConversation(_ conversationID: String)
      @objc optional func didDownloadNonFriend(_ nonFriend: RealmUser)
  
  }
  </code></pre>