*         .build();
   * }
   *
   * <p>Builder instances can be reused; it is safe to call {@link #build} multiple times to build
   * multiple multimaps in series. Each multimap contains the key-value mappings in the previously
   * created multimaps.
   *
   * @since 2.0
   */
  @DoNotMock
  public static class Builder<K, V> {
    @Nullable Map<K, ImmutableCollection.Builder<V>> builderMap;

   *
   * <p>The set's iterator traverses the columns of the first row, the columns of the second row,
   * etc., skipping any columns that have appeared previously.
   */
  @Override
  public Set<C> columnKeySet() {
    Set<C> result = columnKeySet;
    return (result == null) ? columnKeySet = new ColumnKeySet() : result;
  }

  @WeakOuter

     */
    abstract SetBuilderImpl<E> copy();

    /**
     * Call this before build(). Does a final check on the internal data structures, e.g. shrinking
     * unnecessarily large structures or detecting previously unnoticed hash flooding.
     */
    SetBuilderImpl<E> review() {
      return this;
    }

    abstract ImmutableSet<E> build();
  }

     * @param listener the listener to register
     * @throws NullPointerException if {@code listener} is null
     */
    void registerListener(@Nonnull Listener listener);

    /**
     * Unregisters a previously registered listener.
     *
     * @param listener the listener to unregister
     * @throws NullPointerException if {@code listener} is null
     */
    void unregisterListener(@Nonnull Listener listener);

		return nil, err
	}
	if strings.HasSuffix(f.Name, "/") {
		// The ZIP specification (APPNOTE.TXT) specifies that directories, which
		// are technically zero-byte files, must not have any associated file
		// data. We previously tried failing here if f.CompressedSize64 != 0,
		// but it turns out that a number of implementations (namely, the Java
		// jar tool) don't properly set the storage method on directories

        // the common case.
        return;
      }
      PotentialDeadlockException previousDeadlockException = disallowedPriorLocks.get(acquiredLock);
      if (previousDeadlockException != null) {
        // Previously determined to be an unsafe lock acquisition.
        // Create a new PotentialDeadlockException with the same causal chain
        // (the example cycle) as that of the cached exception.

    }

    /**
     * Adds {@code element} to the {@code ImmutableSortedSet}. If the {@code ImmutableSortedSet}
     * already contains {@code element}, then {@code add} has no effect. (only the previously added
     * element is retained).
     *
     * @param element the element to add
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code element} is null
     */

		return "", err
	}
	return hex.EncodeToString(etag), nil
}

// For encrypted objects, the ETag sent by client if available
// is stored in encrypted form in the backend. Decrypt the ETag
// if ETag was previously encrypted.
func getDecryptedETag(headers http.Header, objInfo ObjectInfo, copySource bool) (decryptedETag string) {
	var (
		key [32]byte
		err error
	)
	// If ETag is contentMD5Sum return it as is.

          // This is an upper bound on log2(numerator, ceiling).

          /*
           * We want to do this in long math for speed, but want to avoid overflow. We adapt the
           * technique previously used by BigIntegerMath: maintain separate numerator and
           * denominator accumulators, multiplying the fraction into result when near overflow.
           */
          for (int i = 2; i <= k; i++, n--) {

		if count < readQuorum {
			continue
		}
		partNums = append(partNums, partNum)
	}

	sort.Ints(partNums)
	return partNums, nil
}

// ListObjectParts - lists all previously uploaded parts for a given
// object and uploadID.  Takes additional input of part-number-marker
// to indicate where the listing should begin from.
//
// Implements S3 compatible ListObjectParts API. The resulting