code: function TripDescriptor(properties) {
              if (properties)
                  for (var keys = Object.keys(properties), i = 0; i < keys.length; ++i)
                      if (properties[keys[i]] != null)
                          this[keys[i]] = properties[keys[i]];
          }
docs: Properties of a TripDescriptor.
  @memberof transit_realtime
  @interface ITripDescriptor
  @property {string|null} [tripId] TripDescriptor tripId
  @property {string|null} [routeId] TripDescriptor routeId
  @property {number|null} [directionId] TripDescriptor directionId
  @property {string|null} [startTime] TripDescriptor startTime
  @property {string|null} [startDate] TripDescriptor startDate
  @property {transit_realtime.TripDescriptor.ScheduleRelationship|null} [scheduleRelationship] TripDescriptor scheduleRelationship
   
  Constructs a new TripDescriptor.
  @memberof transit_realtime
  @classdesc Represents a TripDescriptor.
  @implements ITripDescriptor
  @constructor
  @param {transit_realtime.ITripDescriptor=} [properties] Properties to set