Module fill_between 

Fill-between chart builder methods.

This module extends FillBetweenArtist with a fluent API for configuring the visual properties of a filled region between two curves. Since [Axes::fill_between] returns Result<&mut FillBetweenArtist>, these builder methods can be chained directly on the return value:

ax.fill_between(&x, &y1, &y2)?
    .color(Color::rgb(78, 121, 167))
    .label("Confidence interval")
    .alpha(0.3);