Template: integrating \startTextSpan and \stopTextSpan in a customized TextSpanner

If you want to create a music-function for a customized TextSpanner, you may want to integrate \startTextSpan and \stopTextSpan in this function.

The advantage would be to use it like: \customizedTextSpanner { ... }

The following code tries to show a template for it.

A version to use with 2.16.0 is commented.