Writes BufSize bytes to Stream from the memory buffer pointed to by Buffer.
function ConvertWriteStream(Stream: TStream; Buffer: TConversionBuffer; BufSize: Integer): Integer; virtual;
virtual __fastcall int ConvertWriteStream(TStream Stream, TConversionBuffer Buffer, int BufSize);
To convert text between two formats, override this method in a descendant class and convert the text in the buffer. To create a descendant class that TCustomRichEdit can use, convert the text from RTF format.