A contiguous run of matched characters within a candidate string, expressed as a half-open interval [start, end) of UTF-16 code-unit offsets into the original (un-lowercased) candidate.
[start, end)
Offset just past the last matched character (exclusive).
Offset of the first matched character (inclusive).
A contiguous run of matched characters within a candidate string, expressed as a half-open interval
[start, end)of UTF-16 code-unit offsets into the original (un-lowercased) candidate.