rust input field textbox set placeholder

Question

I would like to set the placeholder in the textbox input field, but I am not succeeding.

Can you help me?

use druid::widget::{TextBox, Flex};
use druid::{AppLauncher, Data, Lens, Widget, WidgetExt};

#[derive(Clone, Data, Lens)]
struct AppState {
    text: String,
}

fn main() {
    let main_window = druid::WindowDesc::new(build_ui())
        .title("Window with input field")
        .window_size((400.0, 200.0));

    let initial_state = AppState {
        text: String::new(),
    };

    AppLauncher::with_window(main_window)
        .log_to_console()
        .launch(initial_state)
        .expect("Error launching the app");
}

fn build_ui() -> impl Widget<AppState> {
    let textbox = TextBox::new()
        .lens(AppState::text);

    Flex::column()
        .with_child(textbox)
        .center()
}