Fatshark has a few weird string fields, where they provide a length
field, but then sometimes write a shorter, NUL-terminated string into
that same field and adding padding up to the "advertised" length.
To properly read those strings, we can't rely on just the length field
anymore, but need to check for a NUL, too.
There is no benefit from making all operations on binary data read
in small, async steps directly from the file.
Since we know file sizes beforehand, it's less complex to read
the entire data blob into memory once, then operate on that
synchronously.