code: function processDisplacement(pointers) {
      var delta = processDelta(pointers),
          dx = delta.dx,
          dy = delta.dy,
          velx = delta.velx = Math.abs(dx) / delta.dts,
          vely = delta.vely = Math.abs(dy) / delta.dts,
          direction = delta.direction = getDirection(dx, dy);
  
      delta.distance = getDistance(dx, dy, direction);
      delta.velocity = getOverallVelocity(velx, vely, direction);
          
      return delta;
  }
docs: TODO: processInstantDisplacement (with SAMPLE_INTERVAL) so that we return "instant" velocity for pan gesture