Method error

engine/Poseidon/IO/Streams/QBStream.cpp:644–657

    else
    {
        if (_openBeforeOpenCallback)
        {
            bool ok = _openBeforeOpenCallback(this, _openContext);
            if (!ok)
            {
                _files.Clear();
                CloseHandle(_handle), _handle = nullptr;
                _error = true;
                return false;
            }
        }
    }

    int headerSize = SetFilePointer(_handle, 0, nullptr, FILE_CURRENT);
    BEG_SERIALIZE
    // filemapping uses offset from end of header; direct access uses file offset
    if (_files.NItems() > 0)