public static ValueWrapper getDummyValue(long cas) {
    return new ValueWrapper(null, cas, 0);
  }
For binary protocol we always have to compare the cas version. To avoid turning each put into a
get and replace, use ValueWrapper instances from this method which only uses cas version. note
that equals and hashCode of this class have also been changed to only use the cas version.

@return an instance with null value
geode-memcached/src/main/java/org/apache/geode/internal/memcached/ValueWrapper.java