/// Returns true if the error is a fatal TCP error.
////// Not all errors are fatal, some can be ignored.
pub(crate)fnis_fatal_tcp_error(err:&std::io::Error)->bool{matches!(
err.raw_os_error(),Some(libc::EFAULT)|Some(libc::EINVAL)|Some(libc::ENFILE)|Some(libc::EMFILE)|Some(libc::ENOBUFS)|Some(libc::ENOMEM))}