Some well-known Avahi service types:
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  _adisk._tcp:Apple TimeMachine
  _afpovertcp._tcp:Apple File Sharing
  _airport._tcp:Apple AirPort
  _apt._tcp:APT Package Repository
  _daap._tcp:iTunes Audio Access
  _dacp._tcp:iTunes Remote Control
  _domain._udp:DNS Server
  _dpap._tcp:Digital Photo Sharing
  _ftp._tcp:FTP File Transfer
  _https._tcp:Secure Web Site
  _http._tcp:Web Site
  _imap._tcp:IMAP Mail Access
  _ipps._tcp:Secure Internet Printer
  _ipp._tcp:Internet Printer
  _ldap._tcp:LDAP Directory Server
  _mpd._tcp:Music Player Daemon
  _nfs._tcp:Network File System
  _ntp._udp:NTP Time Server
  _odisk._tcp:DVD or CD Sharing
  _pdl-datastream._tcp:PDL Printer
  _pop3._tcp:POP3 Mail Access
  _postgresql._tcp:PostgreSQL Server
  _printer._tcp:UNIX Printer
  _pulse-server._tcp:PulseAudio Sound Server
  _pulse-sink._tcp:PulseAudio Sound Sink
  _pulse-source._tcp:PulseAudio Sound Source
  _raop._tcp:AirTunes Remote Audio
  _realplayfavs._tcp:RealPlayer Shared Favorites
  _remote-jukebox._tcp:Remote Jukebox
  _rfb._tcp:VNC Remote Access
  _rtp._udp:RTP Realtime Streaming Server
  _rtsp._tcp:RTSP Realtime Streaming Server
  _sftp-ssh._tcp:SFTP File Transfer
  _skype._tcp:Skype VoIP
  _smb._tcp:Microsoft Windows Network
  _ssh._tcp:SSH Remote Terminal
  _telnet._tcp:Telnet Remote Terminal
  _tftp._udp:TFTP Trivial File Transfer
  _timbuktu._tcp:Timbuktu Remote Desktop Control
  _vlc-http._tcp:VLC Streaming
  _workstation._tcp:Workstation
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