message: Support object types without primary keys in the data connector API.
  The object's sync object identifier is used as the object's identity
  when no primary key property is specified.
diff: @@ -185,9 +185,6 @@ public:
  out_object_schema = &*object_schema;
  out_table = ObjectStore::table_for_object_type(m_group, object_type);
  out_primary = out_object_schema->primary_key_property();
  - if (!out_primary) {
  - throw std::runtime_error("Only object types with primary keys can be used in the adapter");
  - }
  }
  }
  }
  