onTapDown method
Implementation
void onTapDown(TapDownDetails details, BuildContext context, Widget widget) {
final localOffset = resolvePositionGestureDetails(details, context, widget);
if (localOffset != null) {
document.cursor.moveTo(localOffset.id, localOffset.offset);
document.selectionManager.collapse();
document.syncPendingFontWithCursor();
document.cursorOnlyUpdate();
}
}