ZLIB how to decompress part of a file?

Question

C++ / C#

The issue is not resolved, but it is no longer relevant.
Mod files use something similar to binary serialization.
Almost all data is there in open form. But some sections are compressed by zlib.
I did not try to isolate this line from the file into different streams. Tried to process with .net GZipStream DeflateStream ZOutputStream classes.
I kept getting the message: unsupported compression method.

In general, help whoever can, I tearfully ask. Preferably in C#

Answer 1

But some sections are compressed by zlib.

zlib has its own signatures (78 01, 78 9C, etc.), and it's hard to understand where compression starts, specifically your question should be asked either there on the forum or from the program developers.