Parsing network response raw data (null byte representation problem)

Hi, everyone. I'm going to parse the data that the viewer handles, which can only be installed through ActiveX in Internet Explorer. Right before the viewer on the web loads the data through Wireshark, they capture the network packet and analyze these rawhex data to extract only the data they want. And we will implement this logic in Android code so that it can be seen in mobile environments.

I know that most of the network packet data I know is that you write the size of the data that will be delivered in the size of the short or int first, and then you write the data that is exactly the size of the byte so that it can be read properly.

But I think these data are mixed up. Some data are in the form of [size][data][00] and others are in the form of [size][data].

In addition, sometimes null is expressed, but this value is expressed as 01. I don't have enough background knowledge yet, so from a short perspective, I doubt how the viewer can parse this data properly. I want to know the parsing rules of this data stream, or the tips on how to read it. Help!