code: def _init():
      
      connection.connect()
  
      # start track
      # all services were provided here:
      # https://android.googlesource.com/platform/system/core/+/jb-dev/adb/SERVICES.TXT
      ready_data = utils.encode_data('host:track-devices')
      connection.adb_socket.send(ready_data)
  
      # get status
      status = connection.adb_socket.recv(4)
  
      # make sure track is ready
      if status != b'OKAY':
          raise RuntimeError('adb server return "{}", not OKAY'.format(str(status)))
docs: build connection and init it