VB NET How to execute some code at the start and at the end of any function

I like to try to optimize my code, and I would like to measure the time taken by a function.

I have a class named Chrono. So I just have to add chrono.start at the beginning of the function, and chrono.stop at the end. My class chan also add the times it measure in a list, to then have average time, total time...

It works. Only problem is when there is exit sub or return in the middle of the function. Not really a problem, I just add a Try at the begginf of the function, and put my chrono.stop in the finally portion. I'm not sure it's really efficient, but it works.

So here is my question : I would like to have a function taking function name as parameter, that will automatically launch and stop my class when this function is called. I have heard of Reflection, but I have no idea how to use it. And it's really hard to search for this question in the internet (because the words are too common : "do something at the end of a function")

To resume, my code works, no problem. It's just constraining to add code to a function for just a short period of time (and sometimes forgot to remove it).

Thx (I'm french and hope I'm understandable)