public short getCrc() {
        return readShort(offset + OFFSET_CRC);
    }
The UDP module  must be able to determine the source and destination internet addresses and
the protocol field from the internet header.

UDP Header Format:

0      7 8     15 16    23 24    31
+--------+--------+--------+--------+
|     Source      |   Destination   |
|      Port       |      Port       |
+--------+--------+--------+--------+
|                 |                 |
|     Length      |    Checksum     |
+--------+--------+--------+--------+
|
|          data octets ...
+---------------- ...

See https://tools.ietf.org/html/rfc768

@author Megatron King
@since 2018-10-10 23:04
netbare-core/src/main/java/com/github/megatronking/netbare/ip/UdpHeader.java