public override int IndexOf(char c, int start, int count) {
// If we got the character from a string its encoding is compatible with the current encoding and thus all characters are single-byte.
Debug.Assert(c <= 0xff);
count = Utils.NormalizeCount(_count, start, count);
return count > 0 ? Array.IndexOf(_data, (byte)c, start, count) : -1;
}