*  Fix: Don't use a cryptographic random number generator for web sockets. Some Android devices
    implement `SecureRandom` incorrectly!
 *  Fix: Correctly canonicalize IPv6 addresses in `HttpUrl`. This prevented OkHttp from trusting
    HTTPS certificates issued to certain IPv6 addresses.
 *  Fix: Don't reuse connections after an unsuccessful `Expect: 100-continue`.

    set("b", "bb", "bbb")

    // Cause the cache trim job to fail.
    filesystem.setFaultyDelete(cacheDir / "a.0", true)
    taskFaker.runNextTask()

    // Confirm that edits are prevented after a cache trim failure.
    assertThat(cache.edit("a")).isNull()
    assertThat(cache.edit("b")).isNull()
    assertThat(cache.edit("c")).isNull()

    // Allow the test to clean up.

   */
  public static CharMatcher isNot(char match) {
    return new IsNot(match);
  }

  /**
   * Returns a {@code char} matcher that matches any BMP character present in the given character
   * sequence. Returns a bogus matcher if the sequence contains supplementary characters.
   */
  public static CharMatcher anyOf(CharSequence sequence) {
    switch (sequence.length()) {

   *
   * @param collection the collection whose complement should be stored in the enum set
   * @return a new, modifiable {@code EnumSet} containing all values of the enum that aren't present
   *     in the given collection
   * @throws IllegalArgumentException if {@code collection} is not an {@code EnumSet} instance and
   *     contains no elements
   */
  @J2ktIncompatible

 * supports `http` and `https`. Use [java.net.URI][URI] for URLs with arbitrary schemes.
 *
 * ### Username and Password
 *
 * Username and password are either present, or the empty string `""` if absent. This class offers
 * no mechanism to differentiate empty from absent. Neither of these components are popular in

    // way for it to return a false negative would be for the target value to jump around in the map
    // such that none of the subsequent iterations observed it, despite the fact that at every point
    // in time it was present somewhere int the map. This becomes increasingly unlikely as
    // CONTAINS_VALUE_RETRIES increases, though without locking it is theoretically possible.
    Segment<K, V, E, S>[] segments = this.segments;
    long last = -1L;

 * never be visible to read or write operations.
 *
 * <p>If {@link #weakKeys weakKeys}, {@link #weakValues weakValues}, or {@link #softValues
 * softValues} are requested, it is possible for a key or value present in the cache to be reclaimed
 * by the garbage collector. Entries with reclaimed keys or values may be removed from the cache on
 * each cache modification, on occasional cache accesses, or on calls to {@link Cache#cleanUp}; such

    * When a pod is deleted, the controller waits for the volume to be safely unmounted by kubelet. It does this by waiting for the volume to no longer be present in the nodes Node.Status.VolumesInUse list. If the volume is not safely unmounted by kubelet within a pre-configured duration (3 minutes in Kubernetes v1.3), the controller unilaterally detaches the volume (this prevents volumes from getting stranded...

         * pending, so its `state` field hasn't been nulled out yet.
         *
         * OK, it's technically possible for this to fail in the presence of unsafe publishing, as
         * discussed in the comments in TimeoutFuture. TODO(cpovirk): Maybe check for null before
         * calling recordOutputCancellation?
         */

     * @param value the value to be associated with the specified key
     * @return the previous value associated with the specified key, or the specified value if the key was not present
     * @see ConcurrentHashMap#putIfAbsent(Object, Object)
     */
    public static <K, V> V putIfAbsent(final ConcurrentMap<K, V> map, final K key, final V value) {
        final V exists = map.putIfAbsent(key, value);