Function seal_export 

async fn seal_export(
    data_outputs: &mut SharedFuel<MzOffset, CapacityContainerBuilder<Vec<(Result<Row, DataflowError>, MzOffset, Diff)>>>,
    cap_set: &mut CapabilitySet<MzOffset>,
    seal: Seal,
    time: MzOffset,
)

Emits the error of seal at time as the final update of its export and drops the export’s capabilities.

The export’s upper advances to the empty frontier once the error is reclocked, which persists that its ingestion has ended. A restarted dataflow excludes exports with an empty upper. One that resumed from its last upper instead would miss every upstream change since the error.

time must be bound by remap while other exports keep running, so it cannot be a placeholder like u64::MAX. Reclock defers an update until remap binds its time and only then drops the export’s capability.