code: def test_mqtt_roundtrip():
      pytest.importorskip("paho.mqtt.client")
      s0 = Stream.from_mqtt(
          "mqtt.eclipseprojects.io", 1883, "streamz/sensor/temperature"
      )
      l = s0.map(lambda msg: msg.payload).sink_to_list()
      s0.start()
  
      data = [b"0123"] * 4
      s = Stream.from_iterable(data)
      s.to_mqtt(
          "mqtt.eclipseprojects.io", 1883, "streamz/sensor/temperature"
      )
      s.start()
  
      wait_for(lambda: data == l, timeout=1)
      s.stop()
      s0.stop()
  
file_path: streamz/streamz/tests/test_sinks.py
imports: import weakref
  import pytest
  from streamz import Stream
  from streamz.sinks import _global_sinks, Sink
  from streamz.utils_test import tmpfile, wait_for
label_desc: Use image node_id 7 for calling a global function with example usage: test_mqtt_roundtrip() without return types