Method upsert

nodedb/src/engine/array/compaction/merger.rs:398–404

(&mut self, new_row: MergedRow)

    }

    fn upsert(&mut self, new_row: MergedRow) {
        if let Some(slot) = self.rows.iter_mut().find(|r| r.coord == new_row.coord) {
            *slot = new_row;
        } else {
            self.rows.push(new_row);
        }
    }

    fn into_sparse(self, schema: &ArraySchema) -> ArrayResult<SparseTile> {
        let mut b = SparseTileBuilder::new(schema);