Function clone_an_object 

fn clone_an_object(
    cx: &mut CurrentRealm<'_>,
    global_scope: &GlobalScope,
    val: HandleValue<'_>,
    seen: &mut HashSet<HashableJSVal>,
    object_handle: HandleObject<'_>,
) -> WebDriverJSResult

https://w3c.github.io/webdriver/#dfn-clone-an-object