Fix -Werror,-Wshorten-64-to-32 issue
Fix -Werror,-Wshorten-64-to-32 issue

Summary: Fix -Werror,-Wshorten-64-to-32 issue

Reviewed By: iahs

Differential Revision: D39303704

fbshipit-source-id: a723a140ac6a0202f3eebf11fd7eba6dc77ec13b

facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift