public void validate(EntityType entityType) { }
 public bool hasChanges(EntityType[] entityTypes) { return false; }
 public EntityQuery toType(EntityType type) { return null; }
 public Entity[] getEntities(EntityType[] entityTypes = null, EntityStateSymbol[] entityStates = null) { return null; }
 public bool hasChanges(EntityType entityType) { return false; }
 public Entity[] getEntities(EntityType entityType, EntityStateSymbol entityState = null) { return null; }
 public Entity[] getChanges(EntityType[] entityTypes) { return null; }
 public Entity[] getChanges(EntityType entityType) { return null; }
 public EntityKey(EntityType entityType, object[] keyValues) { }
 public EntityKey(EntityType entityType, object keyValue) { }