Value of the pickup point order.

PICKUP_POINT_ORDER_UNSPECIFIED Pickup point order unspecified. Default to DISTANCE_FROM_ORIGIN.
DISTANCE_FROM_SEARCH_LOCATION Ascending order of straight-line distance from the search location to the returned pickup point.
WALKING_ETA_FROM_SEARCH_LOCATION Ascending order by the consumer's walking time from the search location to the pickup point.
DRIVING_ETA_FROM_PICKUP_POINT_TO_DESTINATION Ascending order by driving ETA from pickup point to the consumer's destination. This mode can only be used when a destination is set and computeDrivingEta is true. When multiple travelModes are give in request, the ordering is based on the first travelMode in the request.