Function parse_backend_unix_path 

pub fn parse_backend_unix_path(
    unix_path: &str,
) -> Result<SocketAddr, &'static str>

Parse a backend’s unix_path into the socket address sozu dials: an absolute filesystem path, or @name for a Linux abstract-namespace socket. Called at config load, on every AddBackend the main process accepts and on every AddBackend a worker applies, so all three refuse the same values.