NodeConnection(N node) {
      this.node = checkNotNull(node);
    }

    static final class Pred<N> extends NodeConnection<N> {
      Pred(N node) {
        super(node);
      }

      @Override
      public boolean equals(@CheckForNull Object that) {
        if (that instanceof Pred) {
          return this.node.equals(((Pred<?>) that).node);
        } else {
          return false;
        }
      }

    /** Constructor for the header node. */
    AvlNode() {
      this.elem = null;
      this.elemCount = 1;
    }

    // For discussion of pred() and succ(), see the comment on the pred and succ fields.

    private AvlNode<E> pred() {
      return requireNonNull(pred);
    }

    private AvlNode<E> succ() {
      return requireNonNull(succ);
    }

  private void setPredecessor(int entry, int pred) {
    long predMask = ~0L << 32;
    setLink(entry, (link(entry) & ~predMask) | ((long) (pred + 1) << 32));
  }

  private void setSucceeds(int pred, int succ) {
    if (pred == ENDPOINT) {
      firstEntry = succ;
    } else {
      setSuccessor(pred, succ);
    }

    if (succ == ENDPOINT) {
      lastEntry = pred;
    } else {

    /** Constructor for the header node. */
    AvlNode() {
      this.elem = null;
      this.elemCount = 1;
    }

    // For discussion of pred() and succ(), see the comment on the pred and succ fields.

    private AvlNode<E> pred() {
      return requireNonNull(pred);
    }

    private AvlNode<E> succ() {
      return requireNonNull(succ);
    }

      ValueSetLink<K, V> pred, ValueSetLink<K, V> succ) {
    pred.setSuccessorInValueSet(succ);
    succ.setPredecessorInValueSet(pred);
  }

  private static <K extends @Nullable Object, V extends @Nullable Object> void succeedsInMultimap(
      ValueEntry<K, V> pred, ValueEntry<K, V> succ) {
    pred.setSuccessorInMultimap(succ);
    succ.setPredecessorInMultimap(pred);
  }

        Pattern pattern,
        UnsignedInteger ui,
        UnsignedLong ul,
        StringBuilder sb,
        Predicate<?> pred,
        Function<?, ?> func,
        Object obj) {
      delegate.foo(
          s, r, n, it, b, eq, e, in, c, ord, charset, unit, cls, joiner, pattern, ui, ul, sb, pred,
          func, obj);
    }

    @Override
    public String toString() {
      return delegate.toString();
    }

}

func (cred Credentials) String() string {
	var s strings.Builder
	s.WriteString(cred.AccessKey)
	s.WriteString(":")
	s.WriteString(cred.SecretKey)
	if cred.SessionToken != "" {
		s.WriteString("\n")
		s.WriteString(cred.SessionToken)
	}
	if !cred.Expiration.IsZero() && !cred.Expiration.Equal(timeSentinel) {
		s.WriteString("\n")
		s.WriteString(cred.Expiration.String())
	}

	s3Err = authenticateRequest(ctx, r, action)
	reqInfo := logger.GetReqInfo(ctx)
	if reqInfo == nil {
		return cred, owner, ErrAccessDenied
	}

	cred = reqInfo.Cred
	owner = reqInfo.Owner
	if s3Err != ErrNone {
		return cred, owner, s3Err
	}

	return cred, owner, authorizeRequest(ctx, r, action)
}

	// Find the user for the request sender (as it may be sent via a service
	// account or STS account):
	requestorUser := cred.AccessKey
	requestorParentUser := cred.AccessKey
	requestorGroups := cred.Groups
	requestorIsDerivedCredential := false
	if cred.IsServiceAccount() || cred.IsTemp() {
		requestorParentUser = cred.ParentUser
		requestorIsDerivedCredential = true
	}

	// Check if we are creating svc account for request sender.

	r := &http.Request{Header: formValues}
	cred, _, s3Err := checkKeyValid(r, accessKey)
	if s3Err != ErrNone {
		return cred, s3Err
	}
	policy := formValues.Get("Policy")
	signature := formValues.Get(xhttp.AmzSignatureV2)
	if !compareSignatureV2(signature, calculateSignatureV2(policy, cred.SecretKey)) {
		return cred, ErrSignatureDoesNotMatch
	}
	return cred, ErrNone
}