Defines the order that the children appear in, if the horizontal layout overflows.
If the children do not fit into a single row, then they are arranged in a column. The first child is at the top of the column if this property is set to VerticalDirection.down, since it "starts" at the top and "ends" at the bottom. On the other hand, the first child will be at the bottom of the column if this property is set to VerticalDirection.up, since it "starts" at the bottom and "ends" at the top.
Defaults to VerticalDirection.down.
- overflowAlignment, which defines the horizontal alignment of the children within the vertical "overflow" layout.
final VerticalDirection overflowDirection;