Function export_gap_fills 

pub fn export_gap_fills<P: AsRef<Path>>(
    debug_info: &DebugInfo,
    output_path: P,
) -> Result<(), ProjectionError>

Export gap-fill records to a GeoJSON file (phase 6).

Each gap-fill decision becomes a Point feature at the midpoint of the from-netelement’s geometry, with tabular properties describing the pair, whether a route was found, and which bridge NEs were inserted.