Function slider 

pub fn slider(
    ui: &mut Ui<'_>,
    label: &str,
    value: f32,
    min: f32,
    max: f32,
    step: f32,
    tag: impl Into<Value>,
) -> Key

A slider named label over min..=max, at value, moving by step. Its changes arrive as {kind: "change", value, phase, tag} with tag — from the pointer, the arrows, the Page keys, Home / End and assistive technology alike — and the view stores value and draws the slider again at it.