A NewMultiPointFeedback, unlike many other feedback objects, does not return a new geometry or alter the input geometry. Instead, it is used for visual feedback only and relies on you to update a geometry when appropriate. It takes a multipoint object as input and then, when MoveTo is called, it draws a line segment between the current mouse location and each of the points in the multipoint. It should not be confused with the other "New" feedbacks, such as NewLineFeedback, as it serves a very different purpose.