code: func NotifyDepth(depth uint8, kad *Kademlia) {
  	f := func(val *Peer, po int) bool {
  		val.NotifyDepth(depth)
  		return true
  	}
  	kad.EachConn(nil, 255, f)
  }
docs: // NotifyDepth sends a message to all connections if depth of saturation is changed