- Removes the load delay that was previously present after
source preparation.
- Prevents premature failure in the case that the buffering
source fails to prepare.
- SampleSource.Callback will get a second method in a
subsequent CL, approximately meaning "tell me if I can load
more stuff". This will remove the need for LoadControl and
the complexity that comes with it.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=126172573
