Merge pull request #521 from nathanielmanistaatgoogle/future

src/python/src/_framework/face/_calls.py

...future_invocation_asynchronous_event_service_test_case.py

src/python/src/_framework/foundation/_later_test.py

src/python/src/_framework/foundation/_timer_future.py

src/python/src/_framework/foundation/callable_util.py

src/python/src/_framework/foundation/future.py