def METHOD_NAME() -> None:
    global listener_pid
    if listener_pid == os.getpid():
        # Already set up -- and in this process, not just its parent.
        return
    logger.debug("pid %s: tracemalloc_listen working...", os.getpid())
    listener_pid = os.getpid()
    sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
    os.makedirs(settings.TRACEMALLOC_DUMP_DIR, exist_ok=True)
    path = os.path.join(settings.TRACEMALLOC_DUMP_DIR, f"tracemalloc.{os.getpid()}")
    sock.bind(path)
    thread = threading.Thread(target=lambda: tracemalloc_listen_sock(sock), daemon=True)
    thread.start()
    logger.debug("pid %s: tracemalloc_listen done: %s", os.getpid(), path)