All the aws components has to set region as option. Its a string type.
But the AWS client requests to map this to a Region enum class, that has hardcoded all known regions in the AWS SDK. There is about 40 regions in total.
We could make region a Region instead of String in the code, then it will be an enum automatic with those values.
This makes tooling more friendly as they would show a list of enums to choose among.