public DirectionsApiRequest departureTime(Instant time) {
    return param("departure_time", Long.toString(time.toEpochMilli() / 1000L));
  }
Set the departure time for a transit or driving directions request. If both departure time and
traffic model are not provided, then "now" is assumed. If traffic model is supplied, then
departure time must be specified. Duration in traffic will only be returned if the departure
time is specified.

@param time The departure time to calculate directions for.
@return Returns this {@code DirectionsApiRequest} for call chaining.
src/main/java/com/google/maps/DirectionsApiRequest.java