message: [data] AttributeDefinition can include serialization options
  The `AttributeDefinition` interface has been expanded to include:
  * `serializationOptions`
  * `deserializationOptions`
  These options can help specialize a serializer for the given attribute `type`.
diff: @@ -7,6 +7,8 @@ import { Record, RecordInitializer } from './record';
  export interface AttributeDefinition {
  type?: string;
  + serializationOptions?: Dict<any>;
  + deserializationOptions?: Dict<any>;
  }
  export interface RelationshipDefinition {
  