const PointerEvent({Duration timeStamp: Duration.ZERO, int pointer: 0, PointerDeviceKind kind: PointerDeviceKind.touch, int device: 0, Point position: Point.origin, Offset delta: Offset.zero, int buttons: 0, bool down: false, bool obscured: false, double pressure: 1.0, double pressureMin: 1.0, double pressureMax: 1.0, double distance: 0.0, double distanceMax: 0.0, double radiusMajor: 0.0, double radiusMinor: 0.0, double radiusMin: 0.0, double radiusMax: 0.0, double orientation: 0.0, double tilt: 0.0 })

Abstract const constructor. This constructor enables subclasses to provide const constructors so that they can be used in const expressions.

Source 

const PointerEvent({
  this.timeStamp: Duration.ZERO,
  this.pointer: 0,
  this.kind: PointerDeviceKind.touch,
  this.device: 0,
  this.position: Point.origin,
  this.delta: Offset.zero,
  this.buttons: 0,
  this.down: false,
  this.obscured: false,
  this.pressure: 1.0,
  this.pressureMin: 1.0,
  this.pressureMax: 1.0,
  this.distance: 0.0,
  this.distanceMax: 0.0,
  this.radiusMajor: 0.0,
  this.radiusMinor: 0.0,
  this.radiusMin: 0.0,
  this.radiusMax: 0.0,
  this.orientation: 0.0,
  this.tilt: 0.0
});