GCMouse.DidBecomeCurrentMessage
A message that posts after a mouse becomes the most recently used mouse.
Declaration
struct DidBecomeCurrentMessageOverview
Use the .didBecomeCurrent identifier with NotificationCenter to listen for this message.
let observation = NotificationCenter.default.addObserver(of: GCMouse.self, for: .didBecomeCurrent) { message in
let mouse = message.mouse
}