public ClickHouseOutputStream getOutputStream() {
        return output != null ? ClickHouseOutputStream.of(output) : ClickHouseOutputStream.empty();
    }
Gets the output stream for writing. Please pay attention that the returned
output stream has nothing to do with this pass-thru stream, as
{@code getOutputStream().getUnderlyingStream()} is always {@link #NULL}.

@return non-null output stream
clickhouse-data/src/main/java/com/clickhouse/data/ClickHousePassThruStream.java