message: Update signature of prepareCore
diff: @@ -119,7 +119,7 @@ export abstract class CollaborativeObject extends EventEmitter implements IColla
  /**
  * Prepares the given message for processing
  */
  - protected abstract prepareCore(message: ISequencedObjectMessage): Promise<void>;
  + protected abstract prepareCore(message: ISequencedObjectMessage): Promise<any>;
  /**
  * Derived classes must override this to do custom processing on a remote message
  