https://github.com/googleapis/gax-python/blob/master/google/gax/bundling.py#L335 assumes that the `self.timer` will be reset to `None` after it fires, but we don't actually do that. This causes indefinite hangs.
https://github.com/googleapis/gax-python/blob/master/google/gax/bundling.py#L335 assumes that the
self.timerwill be reset toNoneafter it fires, but we don't actually do that. This causes indefinite hangs.