@Override
    public Publisher<Boolean> validate(ValidationDepth validationDepth) {
        if (validationDepth == ValidationDepth.REMOTE) {
            return closed ? just(false) : just(client.ping(node, DEFAULT_TIMEOUT_FOR_CONNECTION_HEALTH_CHECK));
        } else { // validationDepth.LOCAL
            return just(client != null && !closed);
        }
    }
Since transactions are not supported, this method will throw exception.

@param isolationLevel isolation level for transaction
clickhouse-r2dbc/src/main/java/com/clickhouse/r2dbc/connection/ClickHouseConnection.java