`linkConnectionPoint(linkView, view, magnet, reference)` - this function allows you to customize what are the sticky points of links. The function must return a point (with `x` and `y` properties) where the link sticks to the element. The function takes the link view, element view, the magnet (SVG element) the link should stick to and a reference point (either the closest vertex or the sticky point on the other side of the link). Note that there is a utility function shapePerimeterConnectionPoint that can be directly passed to the `linkConnectionPoint` parameter. This function tries to find the best possible connection point right on the perimeter of the connected shapes. See the function documentation for details.