code: func NewAddrBook(filePath string, routabilityStrict bool) *AddrBook {
  	am := &AddrBook{
  		rand:              rand.New(rand.NewSource(time.Now().UnixNano())),
  		ourAddrs:          make(map[string]*NetAddress),
  		addrLookup:        make(map[string]*knownAddress),
  		filePath:          filePath,
  		routabilityStrict: routabilityStrict,
  	}
  	am.init()
  	am.BaseService = *NewBaseService(log, "AddrBook", am)
  	return am
  }
docs: // NewAddrBook creates a new address book.
  // Use Start to begin processing asynchronous address updates.