Setting Zip File Compression Level Doesn't Work

I'm trying to set the compression level to "store" (0).

```
using (ZipFileSystem zfs = ZipFileSystem.CreateZipFile(file, 
FileSystemOptions.Default.AddVariables(new { ZipCompressionLevel = "0" })))
{ ... }
```

This does not seem to work. It is still compressing the file.
