nntp: speed up xover slightly

Reserializing the message to a string to check size wastes
considerable time and should be able to get by with slightly
less accuracy.

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index d5eb4971..fb93330b 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -366,7 +366,8 @@ find_mid:
         }
 found:
         my $o = 'HEAD:' . mid2path($mid);
-        my $s = eval { Email::Simple->new($ng->gcf->cat_file($o)) };
+        my $bytes;
+        my $s = eval { Email::Simple->new($ng->gcf->cat_file($o, \$bytes)) };
         return $err unless $s;
         if ($set_headers) {
                 $s->header_set('Newsgroups', $ng->{name});
@@ -375,7 +376,7 @@ found:
 
                 # must be last
                 if ($set_headers == 2) {
-                        $s->header_set('Bytes', bytes::length($s->as_string));
+                        $s->header_set('Bytes', $bytes);
                         $s->body_set('');
                 }
         }