* creates a new empty iterator.
   */
  protected AbstractSequentialIterator(@CheckForNull T firstOrNull) {
    this.nextOrNull = firstOrNull;
  }

  /**
   * Returns the element that follows {@code previous}, or returns {@code null} if no elements
   * remain. This method is invoked during each call to {@link #next()} in order to compute the
   * result of a <i>future</i> call to {@code next()}.
   */
  @CheckForNull

     * on which it applies.
     *
     * @return the name of the tool option for this path type
     */
    @Nonnull
    Optional<String> option();

    /**
     * Returns the option followed by a string representation of the given path elements.
     * The path elements are separated by an option-specific or platform-specific separator.

/**
 * Package-protected abstract class that implements the line reading algorithm used by {@link
 * LineReader}. Line separators are per {@link java.io.BufferedReader}: line feed, carriage return,
 * or carriage return followed immediately by a linefeed.
 *
 * <p>Subclasses must implement {@link #handleLine}, call {@link #add} to pass character data, and
 * call {@link #finish} at the end of stream.
 *
 * @author Chris Nokleberg
 * @since 1.0

  }

  /**
   * Combines four iterators into a single iterator. The returned iterator iterates across the
   * elements in {@code a}, followed by the elements in {@code b}, followed by the elements in
   * {@code c}, followed by the elements in {@code d}. The source iterators are not polled until
   * necessary.
   *

    private long v3 = 0x7465646279746573L;

    // The number of bytes in the input.
    private long b = 0;

    // The final 64-bit chunk includes the last 0 through 7 bytes of m followed by null bytes
    // and ending with a byte encoding the positive integer b mod 256.
    private long finalM = 0;

    SipHasher(int c, int d, long k0, long k1) {
      super(CHUNK_SIZE);
      this.c = c;

    // 2. It's possible for subscribers to actually be dispatched to in a different order than they
    //    were added to the queue. It's easily possible for one thread to take the head of the
    //    queue, immediately followed by another thread taking the next element in the queue. That
    //    second thread can then dispatch to the subscriber it took before the first thread does.
    //

import org.apache.maven.project.MavenProject;

/**
 * A stub dependency graph that is custom-made for testing concurrent build graph evaluations.
 * <p>
 * Implements a graph as follows:
 * A has no dependencies
 * B depends on A
 * C depends on A
 * X depends on B &amp; C
 * Y depends on B
 * Z depends on C
 * </p>
 *
 */

   * creates a new empty iterator.
   */
  protected AbstractSequentialIterator(@CheckForNull T firstOrNull) {
    this.nextOrNull = firstOrNull;
  }

  /**
   * Returns the element that follows {@code previous}, or returns {@code null} if no elements
   * remain. This method is invoked during each call to {@link #next()} in order to compute the
   * result of a <i>future</i> call to {@code next()}.
   */
  @CheckForNull

    }

    /*
     * Otherwise, approximate the quotient, check, and correct if necessary. Our approximation is
     * guaranteed to be either exact or one less than the correct value. This follows from fact that
     * floor(floor(x)/i) == floor(x/i) for any real x and integer i != 0. The proof is not quite
     * trivial.
     */
    long quotient = ((dividend >>> 1) / divisor) << 1;

      }
      b.append(',').append(' ');
    }
  }

  /**
   * Saves the state to a stream (that is, serializes it).
   *
   * @serialData The length of the array is emitted (int), followed by all of its elements (each a
   *     {@code double}) in the proper order.
   */
  private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
    s.defaultWriteObject();