Function raw_stream 

async fn raw_stream<'a>(
    config: &'a RawSourceCreationConfig,
    replication_client: Client,
    metadata_client: Arc<Client>,
    slot: &'a str,
    timeline_id: &'a Option<u64>,
    publication: &'a str,
    resume_lsn: MzOffset,
    uppers: impl Stream<Item = Antichain<MzOffset>> + 'a,
    probe_output: &'a AsyncOutputHandle<MzOffset, CapacityContainerBuilder<Vec<Probe<MzOffset>>>>,
    probe_cap: &'a Capability<MzOffset>,
) -> Result<Result<impl AsyncStream<Item = Result<ReplicationMessage<LogicalReplicationMessage>, TransientError>> + 'a, DefiniteError>, TransientError>

Produces the logical replication stream while taking care of regularly sending standby keepalive messages with the provided uppers stream.

The returned stream will contain all transactions that whose commit LSN is beyond resume_lsn.