title: iOS Swift cannot set AWSSNSSubscribeInput.protocol parameter
body: <p>I am using Swift for iOS app development in Xcode 6.1.1.</p>
  
  <p>I am trying to programatically subscribe the app to a AWS SNS topic. As I know, you need to set:</p>
  
  <pre><code>let subscriptionRequest = AWSSNSSubscribeInput()
  subscriptionRequest.protocol = "application"
  subscriptionRequest.topicArn = kMyTopicArn
  subscriptionRequest.endpoint = endPointARN
  </code></pre>
  
  <p>But the problem here is the IDE keeps telling me that </p>
  
  <blockquote>
    <p>subscriptionRequest.protocol = "application"</p>
  </blockquote>
  
  <p>is not acceptable and it won't even build.
  <img src="https://i.stack.imgur.com/rTJ9U.png" alt="enter image description here"></p>
  
  <p>Really have no idea how to solve this. Could anyone help here? THANKS!</p>