timestamp
The time when the touch occurred or when it was last mutated.
Declaration
var timestamp: TimeInterval { get }Discussion
The value of this property is the time, in seconds since system startup, that the touch originated or was last changed. You can store the value of this property and compare it to the timestamp in subsequent UITouch objects to determine the duration of the touch and, if it is being swiped, the speed of movement. For a definition of the time since system startup, see the description of the systemUptime method of the ProcessInfo class.