internal static StringBuilder AppendEscaped( [NotNull] this StringBuilder sb, [CanBeNull] string str ) {
if( sb == null ) throw new ArgumentNullException( "sb" );
if( !String.IsNullOrEmpty( str ) ) {
if( str.IndexOf( ',' ) > -1 ) {
int startIndex = sb.Length;
sb.Append( str );
sb.Replace( ',', '\xFF', startIndex, str.Length );
} else {
sb.Append( str );
}
}
return sb;
}