changeCount
The receiver’s change count.
Declaration
var changeCount: Int { get }Discussion
The change count starts at zero when a client creates the receiver and becomes the first owner. The change count subsequently increments each time the pasteboard ownership changes.
The change count is also returned from clearContents() and declareTypes(_:owner:). You can therefore record the value of changeCount at the time that you take ownership of the pasteboard and compare it with a later value to determine whether you still have ownership.