Function report_snapshot_size 

async fn report_snapshot_size(
    client: &Client,
    tables_to_snapshot: &BTreeMap<u32, BTreeMap<usize, SourceOutputInfo>>,
    metrics: PgSnapshotMetrics,
    config: &RawSourceCreationConfig,
    export_statistics: &BTreeMap<(u32, usize), SourceStatistics>,
) -> Result<(), Error>

Record the sizes of the tables being snapshotted in PgSnapshotMetrics and emit snapshot statistics for each export.