requests/requests-ntlm — pull request #50 by ecederstrand (2014-12-11 18:22:13+00:00)
Title: Explicitly close initial connection

The initial socket needs to be explicitly closed to avoid "ResourceWarning: unclosed " warnings from urllib3.

In the self.session case, this is also needed to avoid connection pool starvation. This is observed when sessions are forced to only have one connection:

s = Session()
s.mount('https://', adapters.HTTPAdapter(pool_block=True, pool_connections=1, pool_maxsize=1))