SwiftUI Picker - How to call a function after picker selection

I am looking for a way in SwiftUI to call a function after the Picker value has changed.

At the moment I am using a Button to pas the Picker value into a function and call it but there must be a way to call the function once the picker value has changed?

Any help or direction to reading material would be much appreciated!

Probably better to ask over at the Apple Developer SwiftUI forum. SwiftUI is a private Apple framework, and there are more folks over there that are familiar with the framework that don't hang out on this forum. This forum is for the Swift language itself, not Apple private frameworks.