* {@link IllegalArgumentException} if passed a {@code toKey} greater than an earlier {@code
   * toKey}. However, this method doesn't throw an exception in that situation, but instead keeps
   * the original {@code toKey}.
   */
  @Override
  public ImmutableSortedMap<K, V> headMap(K toKey) {
    return headMap(toKey, false);
  }

  /**

   * {@link IllegalArgumentException} if passed a {@code toKey} greater than an earlier {@code
   * toKey}. However, this method doesn't throw an exception in that situation, but instead keeps
   * the original {@code toKey}.
   */
  @Override
  public ImmutableSortedMap<K, V> headMap(K toKey) {
    return headMap(toKey, false);
  }

  /**

			metaArr[index].VersionID = versionID
			if !metaArr[index].InlineData() {
				// If the data is not inlined, we may end up incorrectly
				// inlining the data here, that leads to an inconsistent
				// situation where some objects are were not inlined
				// were now inlined, make sure to `nil` the Data such
				// that xl.meta is written as expected.
				metaArr[index].Data = nil
			}

			// branch
			xlMeta.data.remove(versionID, dataDir)

			// We need to attempt delete "dataDir" on the disk
			// due to a CopyObject() bug where it might have
			// inlined the data incorrectly, to avoid a situation
			// where we potentially leave "DataDir"
			filePath := pathJoin(volumeDir, path, dataDir)
			if err = checkPathLength(filePath); err != nil {
				return err
			}

 * java.util.Objects#requireNonNull(Object)}. Instead, use whichever of {@link
 * #checkNotNull(Object)} or {@link Verify#verifyNotNull(Object)} is appropriate to the situation.
 * (The same goes for the message-accepting overloads.)
 *
 * <h3>Only {@code %s} is supported</h3>
 *
 * <p>{@code Preconditions} uses {@link Strings#lenientFormat} to format error message template

 * java.util.Objects#requireNonNull(Object)}. Instead, use whichever of {@link
 * #checkNotNull(Object)} or {@link Verify#verifyNotNull(Object)} is appropriate to the situation.
 * (The same goes for the message-accepting overloads.)
 *
 * <h3>Only {@code %s} is supported</h3>
 *
 * <p>{@code Preconditions} uses {@link Strings#lenientFormat} to format error message template

// returns to the caller which dataDir to delete, also
// indicates if this is the last version.
func (x *xlMetaV2) DeleteVersion(fi FileInfo) (string, error) {
	// This is a situation where versionId is explicitly
	// specified as "null", as we do not save "null"
	// string it is considered empty. But empty also
	// means the version which matches will be purged.
	if fi.VersionID == nullVersionID {

 *  New: We've added `requestFailed()` and `responseFailed()` methods to `EventListener`. These
    are called instead of `requestBodyEnd()` and `responseBodyEnd()` in some failure situations.
    They may also be fired in cases where no event was published previously. In this release we did
    an internal rewrite of our event code to fix problems where events were lost or unbalanced.

// Special test type for test with directories
type objTestTypeWithDirs func(obj ObjectLayer, instanceType string, dirs []string, t TestErrHandler)

// Special object test type for disk not found situations.
type objTestDiskNotFoundType func(obj ObjectLayer, instanceType string, dirs []string, t *testing.T)

// ExecObjectLayerTest - executes object layer tests.

   * for matchers that only match a few characters, and so on. In the worst-case scenario, it
   * constructs an eight-kilobyte bit array and queries that. In many situations this produces a
   * matcher which is faster to query than the original.
   */
  @GwtIncompatible // SmallCharMatcher
  CharMatcher precomputedInternal() {
    BitSet table = new BitSet();
    setBits(table);