Summary:
If there's a device client disconnect during request execution, no response is ever given back to the client (flipperd).
This change effectively subscribes to client disconnect events and notifies flipperd of any disconnection during request processing.
Reviewed By: passy
Differential Revision: D37787986
fbshipit-source-id: 31737a50b83b0cbe4141ce814064aebef7e09bfc