Function render 

pub fn render<'scope>(
    key_value: KeyValueLoadGenerator,
    scope: Scope<'scope, MzOffset>,
    config: RawSourceCreationConfig,
    committed_uppers: impl Stream<Item = Antichain<MzOffset>> + 'static,
    start_signal: impl Future<Output = ()> + 'static,
    output_map: BTreeMap<LoadGeneratorOutput, Vec<usize>>,
    idx_to_exportid: BTreeMap<usize, GlobalId>,
) -> (BTreeMap<GlobalId, StackedCollection<'scope, MzOffset, Result<SourceMessage, DataflowError>>>, StreamVec<'scope, MzOffset, Infallible>, StreamVec<'scope, MzOffset, HealthStatusMessage>, Vec<PressOnDropButton>)