def record_viewer(record_json, app_json, key=None) -> str:
    """Create a new instance of "record_viewer", which produces a timeline

    Args:
        record_json: JSON of the record serialized by `json.loads`.

        app_json: JSON of the app serialized by `json.loads`.

    Returns:
        Start time of the selected component in the application. If the whole app is selected,
    """

    # Call through to our private component function. Arguments we pass here
    # will be sent to the frontend, where they'll be available in an "args"
    # dictionary.
    #
    # "default" is a special argument that specifies the initial return
    # value of the component before the user has interacted with it.
    global _record_viewer

    if _record_viewer is None:
        if not _RELEASE:
            _record_viewer = components.declare_component(
                # We give the component a simple, descriptive name
                "record_viewer",
                # Pass `url` here to tell Streamlit that the component will be served
                # by the local dev server that you run via `npm run start`.
                # (This is useful while your component is in development.)
                url="http://localhost:5173",
            )
        else:
            # When we're distributing a production version of the component, we'll
            # replace the `url` param with `path`, and point it to to the component's
            # build directory:
            parent_dir = os.path.dirname(os.path.abspath(__file__))
            build_dir = os.path.join(parent_dir, "dist")
            _record_viewer = components.declare_component(
                "record_viewer", path=build_dir
            )

    component_value = _record_viewer(
        record_json=record_json, app_json=app_json, key=key, default=""
    )

    return component_value
Create a new instance of "record_viewer", which produces a timeline

    Args:
        record_json: JSON of the record serialized by `json.loads`.

        app_json: JSON of the app serialized by `json.loads`.

    Returns:
        Start time of the selected component in the application. If the whole app is selected,
    
src/dashboard/trulens/dashboard/components/record_viewer/__init__.py