Function log_panic_at 

fn log_panic_at(
    path: &Path,
    thread: Option<&str>,
    id: Pid,
    info: &dyn Display,
) -> Result<()>

Send the message of a panic to the journal socket at a path, with the name and the ID of its thread like the default hook, and the location the Display of the PanicHookInfo includes. The process aborts right after, so the message waits for a journal which does not take it right away, on a socket of its own, as the send buffer of the server logs may be full. Without one, like at the limit of open files, which may be what panicked, it goes to the socket of the server logs without waiting.