custom set_exipy is ignored server side when set to 0

[navigator93]

According to the docs, setting the request.session.set_expiry() function to a custom value of 0 should set the cookie to only expire at browser close. It does, in fact set the local cookie's expiry time to blank, however the session middleware (or maybe it is the session app itself), still logs out the user after the global cookie age has passed, effectively ignoring the custom parameter I set. Using a datetime in the future or a value for seconds higher than 0 works just fine. Just not the explicit 0 value.