func perform(Selector, with: Any?, afterDelay : TimeInterval)
func perform(Selector, with: Any?, afterDelay : TimeInterval, inModes : [RunLoop.Mode])
func performSelector (onMainThread : Selector, with: Any?, waitUntilDone : Bool, modes: [String]?)
func perform(Selector, on: Thread, with: Any?, waitUntilDone : Bool)
func perform(Selector, on: Thread, with: Any?, waitUntilDone : Bool, modes: [String]?)
func performSelector (inBackground : Selector, with: Any?)
class func cancelPreviousPerformRequests (withTarget : Any)
perform(_:with:afterDelay:)
instance method.class func cancelPreviousPerformRequests (withTarget : Any, selector: Selector, object: Any?)
perform(_:with:afterDelay:)
.