SendError

pub const SendError = error{
    /// (For UNIX domain sockets, which are identified by pathname) Write permission is  denied
    /// on  the destination socket file, or search permission is denied for one of the
    /// directories the path prefix.  (See path_resolution(7).)
    /// (For UDP sockets) An attempt was made to send to a network/broadcast address as  though
    /// it was a unicast address.
    AccessDenied,

    /// The socket is marked nonblocking and the requested operation would block, and
    /// there is no global event loop configured.
    /// It's also possible to get this error under the following condition:
    /// (Internet  domain datagram sockets) The socket referred to by sockfd had not previously
    /// been bound to an address and, upon attempting to bind it to an ephemeral port,  it  was
    /// determined that all port numbers in the ephemeral port range are currently in use.  See
    /// the discussion of /proc/sys/net/ipv4/ip_local_port_range in ip(7).
    WouldBlock,

    /// Another Fast Open is already in progress.
    FastOpenAlreadyInProgress,

    /// Connection reset by peer.
    ConnectionResetByPeer,

    /// The  socket  type requires that message be sent atomically, and the size of the message
    /// to be sent made this impossible. The message is not transmitted.
    MessageTooBig,

    /// The output queue for a network interface was full.  This generally indicates  that  the
    /// interface  has  stopped sending, but may be caused by transient congestion.  (Normally,
    /// this does not occur in Linux.  Packets are just silently dropped when  a  device  queue
    /// overflows.)
    /// This is also caused when there is not enough kernel memory available.
    SystemResources,

    /// The  local  end  has been shut down on a connection oriented socket.  In this case, the
    /// process will also receive a SIGPIPE unless MSG.NOSIGNAL is set.
    BrokenPipe,

    FileDescriptorNotASocket,

    /// Network is unreachable.
    NetworkUnreachable,

    /// The local network interface used to reach the destination is down.
    NetworkSubsystemFailed,

    /// The destination address is not listening.
    ConnectionRefused,
} || UnexpectedError