Informs the receiver that the user has begun a touch gesture.
- macOS 10.5+
An event object representing the gesture beginning.
The event will be sent to the view under the touch in the key window.
Note that this method is no longer called on apps that link against macOS 10.11 and later. If you need to access the phases of a specific gesture, you can implement the responder for that gesture and examine its
phase property instead.