public void verifyOplogs(LongOpenHashSet foundCrfs, LongOpenHashSet foundDrfs,
      LongOpenHashSet expectedCrfIds, LongOpenHashSet expectedDrfIds) {
    LongOpenHashSet missingCrfs = calcMissing(foundCrfs, expectedCrfIds);
    LongOpenHashSet missingDrfs = calcMissing(foundDrfs, expectedDrfIds);
    // Note that finding extra ones is ok; it is possible we died just
    // after creating one but before we could record it in the if file
    // Or died just after deleting it but before we could record it in the if file.
    boolean failed = false;
    String msg = null;
    if (!missingCrfs.isEmpty()) {
      failed = true;
      msg = "*.crf files with these ids: " + Arrays.toString(missingCrfs.toArray());
    }
    if (!missingDrfs.isEmpty()) {
      failed = true;
      if (msg == null) {
        msg = "";
      } else {
        msg += ", ";
      }
      msg += "*.drf files with these ids: " + Arrays.toString(missingDrfs.toArray());
    }
    if (failed) {
      msg = "The following required files could not be found: " + msg + ".";
      throw new IllegalStateException(msg);
    }
  }
Set of members that have been revoked. We keep track of the revoked members so that we can
indicate to the user a member has been revoked, rather is simply conflicting
geode-core/src/main/java/org/apache/geode/internal/cache/DiskInitFile.java