remove callbacks
fix stop callback Former-commit-id: 1e159e7a215c34b405791d7c588483d25418a1f6 [formerly 986f82c81f5886e3abb8aa8f43c859cc35f66806] [formerly 8c56721f9d3f551f8401e32aa720053a1f9a5514 [formerly 5dedd0d57681c9f1383a23707d10c684311a8f85]] Former-commit-id: 0d9e6906e636faaa846fc74b1948c2ca378ce501 [formerly 68d75e76fef104095b21493ea33fc412f7a3ec32] Former-commit-id: 188a2965810b407f79c9c56f8a63a71e0d8207ba