Based on that interface, I wrote a react native module to bind to it. I have no idea if any public health authorities will be using react native, but if they are, maybe this could give them a head start.
I'm just locked up in my house with nothing to do but try and think of ways to help. Even if it never gets used, I at least learned some things.
https://github.com/codejamninja/react-native-exposure-notification