Close stream connection in case of unexpected error from SAC coordinator

[acogoluegnes]

Calls to the stream SAC coordinator can fail for various reason (e.g. a timeout because of a network partition). The stream reader does not take into account what the SAC coordinator returns and moves on even in case of errors. This can lead to inconsistent state for SAC groups.

A safer alternative would be to handle unexpected errors from the SAC coordinator, close the connection and expect the client to reconnect. This is safer than risking inconsistent state.