trimStart
The optional time, in seconds, at which the animation plays.
Declaration
var trimStart: TimeInterval? { get set }Discussion
This property is nil by default, which plays the animation from the starting frame defined by start.
If you set a value for this property, the animation visually begins from an additional seconds offset from the starting frame and decreases the duration by that amount.
If you set a negative value for this property, the duration increases and the additional animation data fills in based on the fillMode you choose.