Swift で UIAlertController を UIViewController#presentViewController でダイアログ表示するときにエラーが発生。メインスレッドで処理しろ的な。 [t]2015-12-08 12:57:19
This application is modifying the autolayout engine from a background thread, which can lead to engine corruption and weird crashes. [t]2015-12-08 12:57:39