How to have private state in embedded deno_core JsRuntime?

{
    let mut scope = runtime.handle_scope();
    let global = scope.get_current_context().global(&mut scope);

    let key = v8::String::new(&mut scope, "__context").unwrap();
    let context = deno_core::serde_v8::to_v8(&mut scope, &context)?;
    global.set(&mut scope, key.into(), context.into());
};

runtime.execute_script_static("<runtime>", include_str!("runtime.js"))?; // deletes __context
runtime.execute_script_static("<freeze>", include_str!("freeze.js"))?;

let value = runtime.execute_script("<eval>", context.code.into())?; // shouldn't have access to __context
let value = runtime.resolve_value(value).await?;

// get the __context here somehow?