Keep in mind that add the fields here will break backward compatibility. To keep the schema compatible, all new fields need to be placed at the end of the ADAMRecord. For older ADAM files, Avro will just return the default value (which is null).

I can see that once we're all happy on the schema, we might want to make a single breaking change (e.g. 1.0) which cleans up and reorganizes the schema into a form we want to use in production. For now, I recommend putting these fields at the end.