def subscribe(&blk)
      pres = connection.presence_stanza('to'=>jid.bare, 'type' => 'subscribe')
      connection.send_stanza pres, &blk
    end
def subscribe(&blk)
      pres = connection.presence_stanza('to'=>jid.bare, 'type' => 'subscribe')
      connection.send_stanza pres, &blk
    end
sends a subscription request to the bare entity