anchor.diff:  Future<bool> _tableExists(Pool pool, String tablename) {
     Completer<bool> completer = new Completer<bool>();
     var sql = "SELECT EXISTS(SELECT 1 FROM information_schema.tables "
  -      " WHERE table_catalog='gcanvas' AND"
  +      " WHERE table_catalog='gcanvas2' AND"
         " table_schema='public' AND "
         " table_name='$tablename');";
   
  
positive.code:       addressTableExists(pool).then((exists) {
          completer.complete(exists);
        });
      });
    });
  
    return completer.future;
  
negative.code:       addressTableExists(pool).then((exists) {
          completer.complete(exists);
        });
      }, onError: () => print("table resident_response_proxy exists"));
    });
  
    return completer.future;
  