code: func divideContext(ctx context.Context, pointsA, pointsB []schema.Point) []schema.Point {
  	select {
  	case <-ctx.Done():
  		//request canceled
  		return nil
  	default:
  	}
  	return divide(pointsA, pointsB)
  }
docs: // divideContext wraps a Consolidate() call with a context.Context condition