For converting geo_types::LineString<T: CoordFloat> into a piecewise cubic bezier, given as a Vec<BezierSegment<T>>.

BezierSegment<T: CoordFloat> has fields:
start: geo_types::Coord<T>
handles: Option<(geo_types::Coord<T>, geo_types::Coord<T>)>
end: geo_types::Coord<T>

The handles field is None if the segment is a straight line, otherwise the segment is a Cubic Bezier.