You can treat a (tied) filehandle just like any other filehandle. It acts like a filehandle, but maybe its data does reside in memory or somewhere else. As a consumer of data, you usually don't need to care about this.

...
my $fh= $nntp->articlefh(...);
while( <$fh>) {
    print "Article: $_\n";
};
...
[download]