Count characters in a mpg123 string (non-null bytes or UTF-8 characters).
Even with the fill property, the character count is not obvious as there could be multiple trailing null bytes.
\param sb string handle
\param utf8 a flag to tell if the string is in utf8 encoding
\return character count
Count characters in a mpg123 string (non-null bytes or UTF-8 characters). Even with the fill property, the character count is not obvious as there could be multiple trailing null bytes. \param sb string handle \param utf8 a flag to tell if the string is in utf8 encoding \return character count