Restore error handling on client send
Restore error handling on client send

Revert 780f4e26b1c624ab814ff68e6f5fc8a076d5eae5, but adding a timeout instead
of instant default: case. That gives some slack for the client to send back
error if disconnected.

ubuntu/booth-demo-manager,ubuntu/booth-demo-manager,ubuntu/booth-demo-manager,ubuntu/booth-demo-manager