Function measure_multiline_label_with_context 

pub fn measure_multiline_label_with_context(
    label: &str,
    ctx: &LabelSubstContext<'_>,
    font_name: &str,
    font_size: f64,
) -> TextLabelLayout

Measures a multiline plain-text Graphviz label in the charset of the graph being laid out (charset::current); see make_text_label.