9/18    In UDP or multicast/datagram/whatever you call them, is it necessary
        to do CRC or some type of error checking? Or is it guaranteed to not
        have error (either you get correct data or none)?
        \_ my understanding is the latter.  that is what a datagram is
           all about
        \_ From "man udp":
           MIB VARIABLES
           The udp protocol implements a number of variables in the net.inet
           branch of the sysctl(3) MIB.
             UDPCTL_CHECKSUM    (udp.checksum) Enable udp checksums (enabled by
                                default).