Suricata

        while !current.is_empty() {
            SCLogDebug!("request: handling {}", current.len());
            match parse_message(current, self.protocol_version, self.max_msg_len) {
                Ok((rem, msg)) => {
                    let _pdu = Frame::new(
                        flow,
                        &stream_slice,
                        input,
                        current.len() as i64,
                        MQTTFrameType::Pdu as u8,
                    );

The code uses input which is the whole TCP stream, instead of current which is the current PDU