getOffsetForCaret method
Implementation
/// Returns the offset at which to paint the caret.
///
/// Valid only after [layout].
@override
Offset getOffsetForCaret(TextPosition position, Rect caretPrototype) {
assert(!debugNeedsLayout);
_layoutTextWithConstraints(constraints);
return _textPainter.getOffsetForCaret(position, caretPrototype);
}