code: func (ps *peerSet) NodeDataIdlePeers() ([]*peerConnection, int) {
  	idle := func(p *peerConnection) bool {
  		return atomic.LoadInt32(&p.stateIdle) == 0
  	}
  	throughput := func(p *peerConnection) float64 {
  		p.lock.RLock()
  		defer p.lock.RUnlock()
  		return p.stateThroughput
  	}
  	return ps.idlePeers(63, 64, idle, throughput)
  }
docs: // NodeDataIdlePeers retrieves a flat list of all the currently node-data-idle
  // peers within the active peer set, ordered by their reputation.