public boolean isDepartedMember(VersionSource<T> mbr) {
    RegionVersionHolder<T> h = memberToVersion.get(mbr);
    return (h != null) && h.isDepartedMember;
  }
Test hook - see if a member is marked as "departed"
geode-core/src/main/java/org/apache/geode/internal/cache/versions/RegionVersionVector.java