code: def test_async_callback_and_unknown_peer(self):
      client = moolib.Rpc()
      host = moolib.Rpc()
  
      client.set_name("client")
      client.set_timeout(1)
  
      def hello(message):
          return "this is a response to message %s" % repr(message)
  
      host.define("hello", hello)
      host.set_name("host")
      host.listen(ADDRESS)
      client.connect(ADDRESS)
  
      num_calls = 0
      message = "this is a message through async_callback"
  
      def helloCallback(response, error):
          nonlocal num_calls
          num_calls += 1
          assert response == hello(message)
          assert error is None
  
      client.async_callback("host", "hello", helloCallback, message)
  
      future = client.async_(
          "nowhere", "hello", "this is a message to nowhere"
      )
      with pytest.raises(  # TODO: Should this be a RuntimeError?
          RuntimeError,
          match=re.escape("Call (nowhere::<unknown>) timed out"),
      ):
          future.result()
  
      assert num_calls == 1
  
imports: import re
  import pytest
  import moolib
label_desc: Use image node_id 2 for calling the TestMoolib obj's underlying member method code with example usage: obj.test_async_callback_and_unknown_peer() and returns: unknown