The Protobuf object to read from
The end position of the message in the buffer
The ids are used only to provide incrementality support. The id should be unique within a FeedMessage. Consequent FeedMessages may contain FeedEntities with the same id. In case of a DIFFERENTIAL update the new FeedEntity with some id will replace the old FeedEntity with the same id (or delete it - see is_deleted below). The actual GTFS entities (e.g. stations, routes, trips) referenced by the feed must be specified by explicit selectors (see EntitySelector below for more info).
Whether this entity is to be deleted. Relevant only for incremental fetches
OptionalshapeDescribes the physical path that a vehicle takes when it's not part of the (CSV) GTFS, such as for a detour. Shapes belong to Trips, and consist of a sequence of shape points. Tracing the points in order provides the path of the vehicle. Shapes do not need to intercept the location of Stops exactly, but all Stops on a trip should lie within a small distance of the shape for that trip, i.e. close to straight line segments connecting the shape points NOTE: This message is still experimental, and subject to change. It may be formally adopted in the future.
OptionalvehicleRealtime positioning information for a given vehicle.
A definition (or update) of an entity in the transit feed. May be a TripUpdate, VehiclePosition, Alert, Shape, Stop, and/or TripModifications. At least one of the above must be present (unless the entity is being deleted).