Returns whether the user has touched the content to initiate scrolling.
The value of this property is
YES if the user has touched the content view but might not have yet have started dragging it.
Getting the Scrolling State
A Boolean value that indicates whether the user has begun scrolling the content.
Returns whether the content is moving in the scroll view after the user lifted their finger.
A floating-point value that determines the rate of deceleration after the user lifts their finger.