Was a missing call to the update if we had flushed. Now we just do it as part of finishing the flush. Daisy chain it onto the end of the flush future.
Eagerly trigger the timer update -- if the flush takes a while we don't want to double flush in quick succession.
Merge pull request #324 from twitter/feature/fixSummerBug2

Daisy chain update onto the end of the flush future.