*  **RouteDatabase is no longer public API.** OkHttp continues to track which
    routes have failed but this is no exposed in the API.

 *  **ResponseSource is gone.** This enum exposed whether a response came from
    the cache, network, or both. OkHttp 2 offers more detail with raw access to
    the cache and network responses in the new `Response` class.

  /** Returns the element with the specified index. This method is called by {@link #next()}. */
  @ParametricNullness
  protected abstract E get(int index);

  /**
   * Constructs an iterator across a sequence of the given size whose initial position is 0. That
   * is, the first call to {@link #next()} will return the first element (or throw {@link
   * NoSuchElementException} if {@code size} is zero).
   *

    /**
     * {@return the list of patterns for the files to include}.
     * The path separator is {@code /} on all platforms, including Windows.
     * The prefix before the {@code :} character, if present and longer than 1 character, is the syntax.
     * If no syntax is specified, or if its length is 1 character (interpreted as a Windows drive),
     * the default is a Maven-specific variation of the {@code "glob"} pattern.
     *

   *
   * (The index actually stored is the index of the key in alternatingKeysAndValues, which is
   * double the index of the entry in entrySet.asList.)
   *
   * The basic data structure is described in https://en.wikipedia.org/wiki/Open_addressing.
   * The pointer to a key is stored in hashTable[Hashing.smear(key.hashCode()) % table.length],
   * save that if that location is already full, we try the next index, and the next, until we

     *
     * @param message the detail message (which is saved for later retrieval
     *                by the {@link #getMessage()} method).
     * @param cause   the cause (which is saved for later retrieval by the
     *                {@link #getCause()} method). A {@code null} value is
     *                permitted, and indicates that the cause is nonexistent or unknown.
     */

            "A notify change request is being completed.", "The data was too large to fit into the specified buffer.",
            "A device attached to the system is not functioning.", "Incorrect function.", "The parameter is incorrect.",
            "Invalid access to memory location.", "The handle is invalid.", "The parameter is incorrect.",

   * and response body streams; otherwise resources may be leaked.
   *
   * This method is safe to be called concurrently, but provides limited guarantees. If a transport
   * layer connection has been established (such as a HTTP/2 stream) that is terminated. Otherwise
   * if a socket connection is being established, that is terminated.
   */
  override fun cancel() {
    if (canceled) return // Already canceled.

 * that they are safe for concurrent use, but if other threads modify the map after the iterator is
 * created, it is undefined which of these changes, if any, are reflected in that iterator. These
 * iterators never throw {@link ConcurrentModificationException}.
 *
 * <p>If {@link #weakKeys} or {@link #weakValues} are requested, it is possible for a key or value

 * this class separates _allocations_ from _streams_. An allocation is created by a call, used for
 * one or more streams, and then released. An allocated connection won't be stolen by other calls
 * while a redirect or authorization challenge is being handled.
 *
 * When the maximum concurrent streams limit is reduced, some allocations will be rescinded.
 * Attempting to create new streams on these allocations will fail.

        assertThat(ObjectUtil.equals(null, null), is(true));
        assertThat(ObjectUtil.equals(null, ""), is(false));
        assertThat(ObjectUtil.equals("", null), is(false));
        assertThat(ObjectUtil.equals("", ""), is(true));
        assertThat(ObjectUtil.equals(Boolean.TRUE, null), is(false));
        assertThat(ObjectUtil.equals(Boolean.TRUE, "true"), is(false));