feature request: file size of remote zip file

[relikd]

Unfortunatelly summing up all uncompressed sizes of all zipped entries is not equivalent to the filesize if I were to download a zip file. I guess thats because the zip file itself has metadata etc.
Therefore, I would like to store the file size of the remote file and make it available to the RemoteZip class. I think this should be the output of RemoteFetcher.get_file_size()?

[relikd]

But unfortunately this results in the same problem I had while searching for a manual solution. It does not handle redirects well. HEAD will have no content-length on HTTP 304.

[relikd]

zip.fp.tell() seems to work, though I dont know if tell is available in all cases and if it will always be EOF?

[gtsystem]

Correct file size can be found in zip.fp._file_size. I suppose we could expose this under zip.size(). Would you like to provide a PR?