Comment 6 for bug 1363722

This is a bug/limitation in the standard library code we're using in apiclient to generate the request - anything 1.5GB or larger isn't going to upload with the current code.

A couple of options to fix this:

1. Try to get the email.generator code fixed in upstream python - it could use BytesIO instead of StringIO, maybe.
2. Provide our own Generator that uses BytesIO instead, or performs multiple writes() that are less than 2GB each.