man LWP::ConnCache constain missleading info,
The section below

           $cache->drop(22, "Older than 22 secs dropped");
           # which is just a synonym for:
           $cache->drop(sub {
               my ($conn, $type, $key, $deposit_time) = @_;
               if ($deposit_time < 22) {
                   # true values drop the connection
                   return 1;
               }
               # false values don't drop the connection
               return 0;
           }, "Older than 22 secs dropped" );

should be corrected to

               if ($deposit_time < time - 22) {