pub fn peer_cred(socket: &UnixStream) -> Result<UCred>Available on (Android or Apple or Cygwin or DragonFly BSD or FreeBSD or Linux or NetBSD or OpenBSD or QNX Neutrino) and (Android or Cygwin or Linux) and non-Hermit and not ((Fortanix and SGX, or WebAssembly and non-WASI)) and (Unix) only.