Method do_get_fallback

datafusion-examples/examples/flight/sql_server.rs:247–282

(
        &self,
        _request: Request<Ticket>,
        message: Any,
    )

    }

    async fn do_get_fallback(
        &self,
        _request: Request<Ticket>,
        message: Any,
    ) -> Result<Response<<Self as FlightService>::DoGetStream>, Status> {
        if !message.is::<FetchResults>() {
            Err(Status::unimplemented(format!(
                "do_get: The defined request is invalid: {}",
                message.type_url
            )))?
        }

        let fr: FetchResults = message
            .unpack()
            .map_err(|e| Status::internal(format!("{e:?}")))?
            .ok_or_else(|| Status::internal("Expected FetchResults but got None!"))?;

        let handle = fr.handle;

        info!("getting results for {handle}");
        let result = self.get_result(&handle)?;
        // if we get an empty result, create an empty schema
        let (schema, batches) = match result.first() {
            None => (Arc::new(Schema::empty()), vec![]),
            Some(batch) => (batch.schema(), result.clone()),
        };

        let batch_stream = futures::stream::iter(batches).map(Ok);

        let stream = FlightDataEncoderBuilder::new()
            .with_schema(schema)
            .build(batch_stream)
            .map_err(Status::from);

        Ok(Response::new(Box::pin(stream)))
    }

    async fn get_flight_info_prepared_statement(
        &self,