Base class for the server implementation of the service FleetRouting.
A service for optimizing vehicle tours.
Validity of certain types of fields:
* `google.protobuf.Timestamp`
* Times are in Unix time: seconds since 1970-01-01T00:00:00+00:00.
* seconds must be in [0, 253402300799],
i.e. in [1970-01-01T00:00:00+00:00, 9999-12-31T23:59:59+00:00].
* nanos must be unset or set to 0.
* `google.protobuf.Duration`
* seconds must be in [0, 253402300799],
i.e. in [1970-01-01T00:00:00+00:00, 9999-12-31T23:59:59+00:00].
* nanos must be unset or set to 0.
* `google.type.LatLng`
* latitude must be in [-90.0, 90.0].
* longitude must be in [-180.0, 180.0].
* at least one of latitude and longitude must be non-zero.