Creates a segmented control that supports SPA navigation.
You should always use this instead of view when building a SPA
and the segmented control options correspond to routes in the SPA.
The first parameter is a function that takes a route and returns the URL of that route.
onClick: the message to produce when an option is selected (clicked) by the useroptions: the list of options availableselected: the value of the currently-selected optionwidth: how to size the segmented controlcontent: the panel content for the selected option