gRPC service definition for the Arrow Flight protocol.
Only the RPCs required by the InfluxDB v3 Flight query path are defined here:
DoGet— streamsFlightDatafor a givenTicketGetFlightInfo— returnsFlightInfofor aFlightDescriptor
The full Flight spec also includes Handshake, ListFlights, DoPut,
DoAction, ListActions, and DoExchange; these can be added as needed.