The default directionality of the text.
This is also used to disambiguate how to render bidirectional text. For example, if the text string is an English phrase followed by a Hebrew phrase, in a TextDirection.ltr context the English phrase will be on the left and the Hebrew phrase to its right, while in a TextDirection.rtl context, the English phrase will be on the right and the Hebrew phrase on its left.
It is default to TextDirection.ltr. This default value is only for conciseness. We cherish the diversity of cultures, and insist that not any language habit should be regarded as "default".
final TextDirection? textDirection;