code: func (nmgr *natManager) NAT() *inat.NAT {
  	nmgr.natmu.Lock()
  	defer nmgr.natmu.Unlock()
  	return nmgr.nat
  }
docs: // NAT returns the natManager's nat object. this may be nil, if
  // (a) the search process is still ongoing, or (b) the search process
  // found no nat. Clients must check whether the return value is nil.