code: def nl_send_iovec(sk, msg, iov, _):
      
      hdr = msghdr(msg_name=sk.s_peer, msg_iov=iov)
  
      # Overwrite destination if specified in the message itself, defaults to the peer address of the socket.
      dst = nlmsg_get_dst(msg)
      if dst.nl_family == socket.AF_NETLINK:
          hdr.msg_name = dst
  
      # Add credentials if present.
      creds = nlmsg_get_creds(msg)
      if creds:
          raise NotImplementedError  # TODO https://github.com/Robpol86/libnl/issues/2
  
      return nl_sendmsg(sk, msg, hdr)
docs: Transmit Netlink message.
  
      https://github.com/thom311/libnl/blob/libnl3_2_25/lib/nl.c#L342
  
      This function is identical to nl_send().
  
      This function triggers the `NL_CB_MSG_OUT` callback.
  
      Positional arguments:
      sk -- Netlink socket (nl_sock class instance).
      msg -- Netlink message (nl_msg class instance).
      iov -- data payload to be sent (bytearray).
  
      Returns:
      Number of bytes sent on success or a negative error code.