boolean isSameDSMember(ClientProxyMembershipID that) {
    if (that != null) {
      // Test whether:
      // - the durable ids are equal (if durable) or
      // - the identities are equal (if non-durable)
      return isDurable() ? getDurableId().equals(that.getDurableId())
          : Arrays.equals(identity, that.identity);
    } else {
      return false;
    }
  }
Return true if "that" can be used in place of "this" when canonicalizing.
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/ClientProxyMembershipID.java