fix compile error when use empty_callback
fix compile error when use empty_callback

Summary: Ref T8010

Test Plan: N/A

Reviewers: shenyuannan, cailiuyang, sunweijie

Reviewed By: sunweijie

Subscribers: #pegasus

Maniphest Tasks: T8010

Differential Revision: https://phabricator.d.xiaomi.net/D50532

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