Function pane_lost_connection 

pub fn pane_lost_connection(code: Option<u32>, stopped_by_srv: bool) -> bool

Whether a pane’s ssh, ended with code, lost its connection (or never had one). stopped_by_srv: srv ended it itself (the pane closed, or restarted), and ssh then exits 255 too (closing its pty does, and a session on a shared connection does on SIGTERM), which is no lost connection.