<summary> Offset in the advance direction of the run. A positive advance offset moves the glyph to the right (in pre-transform coordinates) if the run is left-to-right or to the left if the run is right-to-left. </summary>
See Implementation
<summary> Offset in the advance direction of the run. A positive advance offset moves the glyph to the right (in pre-transform coordinates) if the run is left-to-right or to the left if the run is right-to-left. </summary>