Function build_timeline_data 

pub fn build_timeline_data(
    tag: &str,
    total_s: f64,
    dlg: Vec<Label>,
    amb: Vec<Label>,
    mus: Vec<Label>,
    sfx: Vec<Label>,
    vf: Vec<Label>,
    sections: Vec<Label>,
    scenes: Vec<Label>,
) -> TimelineData

build_timeline_data(...).