Returns whether the content is moving in the scroll view after the user lifted their finger.
The returned value is
YES if user isn't dragging the content but scrolling is still occurring.
Getting the Scrolling State
Returns whether the user has touched the content to initiate scrolling.
A Boolean value that indicates whether the user has begun scrolling the content.
A floating-point value that determines the rate of deceleration after the user lifts their finger.