Base class for flow containers. Arranges child [Control] nodes vertically or horizontally in a left-to-right or top-to-bottom flow. A line is filled with [Control] nodes until no more fit on the same line, similar to text in an autowrapped label. Returns the current line count. The alignment of the container's children (must be one of [constant ALIGNMENT_BEGIN], [constant ALIGNMENT_CENTER], or [constant ALIGNMENT_END]). If [code]true[/code], the [FlowContainer] will arrange its children vertically, rather than horizontally. Can't be changed when using [HFlowContainer] and [VFlowContainer]. The child controls will be arranged at the beginning of the container, i.e. top if orientation is vertical, left if orientation is horizontal (right for RTL layout). The child controls will be centered in the container. The child controls will be arranged at the end of the container, i.e. bottom if orientation is vertical, right if orientation is horizontal (left for RTL layout). The horizontal separation of children nodes. The vertical separation of children nodes.