code: function isAvailable(state, feed_id, ignore_id) {
    for(var peer_id in state.peers) {
      if(peer_id != ignore_id) {
        var peer = state.peers[peer_id]
        //BLOCK: check wether id has blocked this peer
        if((peer.clock && peer.clock[feed_id] || 0) > (state.clock[feed_id] || 0) && isShared(state, feed_id, peer_id)) {
          return true
        }
      }
    }
  }
docs: check if a feed is available from a peer apart from ignore_id