sealed class AlignmentLine
Defines a layout line that can be used by layout models to align and position layout children.
When a Layout or ComplexLayout provides a value for a particular AlignmentLine, this can
be read by the parent of the layout after measuring, using the corresponding Placeable
instance. Also, the value will be automatically inherited by the parent which will offset
the value by the position of the child within itself.
AlignmentLines cannot be created directly, please create VerticalAlignmentLine or
HorizontalAlignmentLine instances instead.