protected CompletableFuture<ClickHouseResponse> failedResponse(Throwable ex) {
        CompletableFuture<ClickHouseResponse> future = new CompletableFuture<>();
        future.completeExceptionally(ex);
        return future;
    }
Base class for implementing a thread-safe ClickHouse client. It uses
{@link ReadWriteLock} to manage access to underlying connection.
clickhouse-client/src/main/java/com/clickhouse/client/AbstractClient.java