GestureTapDragStartCallback typedef
Signature for when a pointer has contacted the screen and has begun to move.
The details
object provides the position of the touch when it first
touched the surface.
The consecutive tap count at the time the pointer contacted the screen is given by TapDragStartDetails.consecutiveTapCount.
Implementation
typedef GestureTapDragStartCallback = void Function(TapDragStartDetails details);