title: Alamofire JSON serialization error - Swift 2.0
body: <p>I'm having issues posting JSON via Alamofire.  I'm getting the error below.  My parameters are as noted - any idea what I'm doing wrong?</p>
  
  <pre><code>    let parameters: [String: AnyObject] = [
          "t": [
              "name": "foo",
              "event": "tap",
              "ts":  NSDate().timeIntervalSince1970
          ],
          "z": [["key": "12345"], ["key": "67890"]]
      ]
  
  Alamofire.request(.POST, "https://myapi.com/test", parameters: parameters, encoding: .JSON)
  </code></pre>
  
  <p>Error Domain=com.alamofire.error Code=-6006 "JSON could not be serialized. Input data was nil or zero length." UserInfo={NSLocalizedFailureReason=JSON could not be serialized. Input data was nil or zero length.}</p>