editingWidth property
Minimum number of "right" keystrokes needed to move the cursor pass through this node (from the rightmost of the previous node, to the leftmost of the next node)
Used only for editing functionalities.
editingWidth stores intrinsic width in the editing mode.
Please calculate (and cache) the width based on children's widths. Note that it should strictly simulate the movement of the curosr.
Implementation
@override
int get editingWidth => 1;