Race condition due to transfer future done_callback that depends on state that may set after it's execution #177

[clehene]

---

This checklist is used to make sure that common guidelines for a pull request are followed.

Description of the change

General Guidelines

• The PR has modified HISTORY.rst with an appropriate description of the change and a version increment.
• The PR has supporting test coverage that confirm the expected behavior and protects against regressions, including necessary recordings.
• Links to associated bugs, if any, are in the description.

[msftclas]

@clehene,
Thanks for having already signed the Contribution License Agreement. Your agreement was validated by Microsoft. We will now review your pull request.
Thanks,
Microsoft Pull Request Bot

[coveralls]

Coverage increased (+1.02%) to 83.576% when pulling 4b3171d on clehene:issue-177 into 622ad04 on Azure:master.

[begoldsm]

This makes sense to me, thanks for identifying this race condition bug!