Add client cert option to zero copy client
Add client cert option to zero copy client

Differential Revision: D30384470

fbshipit-source-id: 97cb36d98b6834c8b338697526295d89e696f634

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