Sends bytes through a socket to its connected peer.
    The $QIO equivalent is the IO$_WRITEVBLK function.
    Format
      #include  <types.h>
      #include  <socket.h>
      int send  ( int s, char *msg, int len, int flags );
                (_DECC_V4_SOURCE)
      ssize_t send  ( int s, const void *msg, size_t len, int flags
                    ); (not_DECC_V4_SOURCE)