I was trying to derive my own parser from FileParser, but when I went to call the constructor for FTPFile (FTPFile(int type, string raw, string name, long size, bool isDir, ref DateTime lastModified)), I wasn't able to access it, because it is internal (all the member variables are protected internal as well, with no public set accessors). Because of this, my parser is unable to return an FTPFile object that contains any relevant data (unless I include the parser in the same assembly, and recompile edtfptnet as a new dll).
