Function write_diff_ansi_to 

pub fn write_diff_ansi_to<W: Write>(
    writer: &mut W,
    front: &Buffer,
    back: &Buffer,
    width: u16,
    height: u16,
    areas: Option<&[Rect]>,
) -> Result<PresentStats>

Streams a Scrin diff directly to any writer and returns presentation stats.