read-only
The offsets of the row boundaries in the grid.
The first offset is the offset of the top edge of the top-most tile from the top edge of the interior of the grid's padding (usually if the padding is EdgeOffsets.zero). The difference between successive entries is the tile height plus the row spacing
The last offset is the offset of the bottom edge of the bottom-most tile from the top edge of the interior of the grid's padding. (less the rowSpacing)
If there are n rows in the grid, there should be n + 1 entries in this list. The bottom edge of the last row is defined as rowOffsets(n), i.e. the top edge of an extra row.