A filament retraction (retract) or its reversal (unretract) — an E-only move
with no XYZ travel, so it has a position but no segment in the main stream
(DD-009 D1 amendment, #148). Kept in a sparse side channel so segment indices,
scrub, and layer ranges are untouched. segIndex is the index of the next
segment emitted after the event, for layer/scrub-aligned marker clipping.
A filament retraction (
retract) or its reversal (unretract) — an E-only move with no XYZ travel, so it has a position but no segment in the main stream (DD-009 D1 amendment, #148). Kept in a sparse side channel so segment indices, scrub, and layer ranges are untouched.segIndexis the index of the next segment emitted after the event, for layer/scrub-aligned marker clipping.