* </pre>
   *
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */
  public static Throwable getRootCause(Throwable throwable) {
    // Keep a second pointer that slowly walks the causal chain. If the fast pointer ever catches
    // the slower pointer, then there's a loop.
    Throwable slowPointer = throwable;
    boolean advanceSlowPointer = false;

   * </pre>
   *
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */
  public static Throwable getRootCause(Throwable throwable) {
    // Keep a second pointer that slowly walks the causal chain. If the fast pointer ever catches
    // the slower pointer, then there's a loop.
    Throwable slowPointer = throwable;
    boolean advanceSlowPointer = false;

  private static void testBytes(int numBytes, long expectedCount) {
    testBytes(numBytes, expectedCount, 0, -1);
  }

  /**
   * Helper to run the loop to test all the permutations for the number of bytes specified. This
   * overload is useful for debugging to get the loop to start at a certain character.
   *
   * @param numBytes the number of bytes in the byte array

  private static final String ERROR_ADDED_PARALLEL_EDGE =
      "Should not be allowed to add a parallel edge.";
  private static final String ERROR_ADDED_SELF_LOOP =
      "Should not be allowed to add a self-loop edge.";
  static final String ERROR_SELF_LOOP = "self-loops are not allowed";

  @Test
  public void transitiveClosure_directedGraph() {

                // Remove the waiter, one way or another we are done parking this thread.
                removeWaiter(node);
                break long_wait_loop; // jump down to the busy wait loop
              }
            }
          }
          oldHead = waiters; // re-read and loop.
        } while (oldHead != Waiter.TOMBSTONE);
      }
      // re-read value, if we get here then we must have observed a TOMBSTONE while trying to add a

    // Special case some of the weird HTTP Header names...
    ImmutableBiMap<String, String> specialCases =
        ImmutableBiMap.<String, String>builder()
            .put("CDN_LOOP", "CDN-Loop")
            .put("ETAG", "ETag")
            .put("SOURCE_MAP", "SourceMap")
            .put("SEC_CH_UA_WOW64", "Sec-CH-UA-WoW64")
            .put("SEC_WEBSOCKET_ACCEPT", "Sec-WebSocket-Accept")

    GraphConnections<N, V> connections = nodeConnections.get(node);
    if (connections == null) {
      return false;
    }

    if (allowsSelfLoops()) {
      // Remove self-loop (if any) first, so we don't get CME while removing incident edges.
      if (connections.removeSuccessor(node) != null) {
        connections.removePredecessor(node);
        --edgeCount;
      }
    }

  // here too.
  static final String ERROR_MODIFIABLE_SET = "Set returned is unexpectedly modifiable";
  static final String ERROR_SELF_LOOP = "self-loops are not allowed";
  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";

  /** Creates and returns an instance of the graph to be tested. */
  abstract Graph<Integer> createGraph();

  /**

  private static void testBytes(int numBytes, long expectedCount) {
    testBytes(numBytes, expectedCount, 0, -1);
  }

  /**
   * Helper to run the loop to test all the permutations for the number of bytes specified. This
   * overload is useful for debugging to get the loop to start at a certain character.
   *
   * @param numBytes the number of bytes in the byte array

   * @return a long of a concatenated 8 bytes
   */
  static long load64(byte[] input, int offset) {
    // We don't want this in production code as this is the most critical part of the loop.
    assert input.length >= offset + 8;
    // Delegates to the fast (unsafe) version or the fallback.
    return byteArray.getLongLittleEndian(input, offset);
  }

  /**