In the Compiler Plugin we right now use the `@RealmObject` annotation, but we need to figure out exactly what the API for working with Realm Objects should look like.

In Realm Java we have both an abstract RealmObject super class and a RealmModel marker interface. 

With default methods on interfaces we can probably get away with just an interface for Kotlin/Java 8, but we need to figure out the exact semantics.

QUESTIONS / TODO

• How should a Realm Object be identifier?

• What about DynamicRealmObject / Embedded Objects?
• Interface default methods have some limitations, ie. we cannot have "default properties". Figure out exactly what is possible.
• If we don't have a state on the marker interface, how would people access it?
• How do people register observers on objects?
• Writeup design doc with pros/cons for different solutions