Send an archive created on the fly by Archive_Tar .
The parameter $files can be an array of files/directories or a space separated string of files/directories which should be packed to an archive.
string $name - the name the archive should have
mixed $files - list of files/directories
string [$type = HTTP_DOWNLOAD_TGZ] - the format of the archive (TAR, TGZ, BZ2 or ZIP)
string [$add_path = ''] - path that should be prepended to the files
string [$strip_path = ''] - path that should be stripped from the files