use gpui::actions;use ui::prelude::*; actions!(    panel,    [        /// Navigates to the next tab in the panel.        NextPanelTab,        /// Navigates to the previous tab in the panel.        PreviousPanelTab    ]); pub trait PanelHeader: workspace::Panel {} /// Implement this trait to enable a panel to have tabs.pub trait PanelTabs: PanelHeader {    /// Returns the index of the currently selected tab.    fn selected_tab(&self, cx: &mut App) -> usize;    /// Selects the tab at the given index.    fn select_tab(&self, cx: &mut App, index: usize);    /// Moves to the next tab.    fn next_tab(&self, _: NextPanelTab, cx: &mut App) -> Self;    /// Moves to the previous tab.    fn previous_tab(&self, _: PreviousPanelTab, cx: &mut App) -> Self;} #[derive(IntoElement)]pub struct PanelTab {} impl RenderOnce for PanelTab {    fn render(self, _window: &mut Window, _cx: &mut App) -> impl IntoElement {        div()    }}