@Override
    public void fromData(DataInput in,
        DeserializationContext context) throws IOException, ClassNotFoundException {
      key = InternalDataSerializer.readByteArray(in);
      value = InternalDataSerializer.readByteArray(in);
    }
Returns the size in bytes of the serialized key and value.

@return the record size
geode-core/src/main/java/org/apache/geode/internal/cache/snapshot/SnapshotPacket.java