@Override
  public DiskStoreID readMember(DataInput in) throws IOException {
    long mostSignificantBits = in.readLong();
    long leastSignificantBits = in.readLong();
    DiskStoreID member = new DiskStoreID(mostSignificantBits, leastSignificantBits);
    return member;
  }
For a persistent version tag, the member id should not be null, because we can't fill the
member id in later.
geode-core/src/main/java/org/apache/geode/internal/cache/versions/DiskVersionTag.java