NSDraggingSession
The encapsulation of a drag-and-drop action that supports modification of the drag while in progress.
Declaration
class NSDraggingSessionOverview
You start a new dragging session by calling the NSView method beginDraggingSession(with:event:source:) method. This method immediately returns and you can further modify the properties of the dragging session. The actual drag begins at the next turn of the run loop.