Exact frozen revision to process.
Host processing engine, retaining its configured limits/projections/scheduler.
Original local bytes; present for image-dependent exports.
Current fit, or null for formats permitting unfinished sessions.
Report normalized progress from 0 to 1.
Read-only borrowed preview for reports; never transfer its data buffer.
Aborted on cancellation, supersession, re-alignment or suspension.
Revision identity for worker jobs.
Captured inputs for one export. Never mutate or retain shared preview pixels.