public void MoveNext()
{
// For ill-formed subsequences (like unpaired UTF-16 surrogate code points), we rely on
// the decoder's default behavior of interpreting these ill-formed subsequences as
// equivalent to U+FFFD REPLACEMENT CHARACTER. This code point has a boundary property
// of Other (XX), which matches the modifications made to UAX#29, Rev. 35.
// See: https://www.unicode.org/reports/tr29/tr29-35.html#Modifications
// This change is also reflected in the UCD files. For example, Unicode 11.0's UCD file
// https://www.unicode.org/Public/11.0.0/ucd/auxiliary/GraphemeBreakProperty.txt
// has the line "D800..DFFF ; Control # Cs [2048] <surrogate-D800>..<surrogate-DFFF>",
// but starting with Unicode 12.0 that line has been removed.
//
// If a later version of the Unicode Standard further modifies this guidance we should reflect
// that here.
CurrentCodeUnitOffset += _codeUnitLengthOfCurrentScalar;
_decoder(_buffer.Slice(CurrentCodeUnitOffset), out Rune thisRune, out _codeUnitLengthOfCurrentScalar);
CurrentType = CharUnicodeInfo.GetGraphemeClusterBreakType(thisRune);
}