* has elapsed after the entry's creation, or the most recent replacement of its value.
   *
   * <p>When {@code duration} is zero, this method hands off to {@link #maximumSize(long)
   * maximumSize}{@code (0)}, ignoring any otherwise-specified maximum size or weight. This can be
   * useful in testing, or to disable caching temporarily without a code change.
   *

   * CharMatcher.is('a').replaceFrom("yaha", "oo")
   * }</pre>
   *
   * ... returns {@code "yoohoo"}.
   *
   * <p><b>Note:</b> If the replacement is a fixed string with only one character, you are better
   * off calling {@link #replaceFrom(CharSequence, char)} directly.
   *
   * @param sequence the character sequence to replace matching characters in

              }
              i++;
              /*
               * The cast is safe because of the containsKey check in hasNext(). (That means it's
               * unsafe under concurrent modification, but all bets are off then, anyway.)
               */
              return uncheckedCastNullableTToT(map.get(key));
            }

            @Override
            public void remove() {
              checkRemove(i == 1);

  //   have observed 12 micros on 64-bit linux systems to wake up a parked thread). So if the
  //   timeout is small we shouldn't park(). This needs to be traded off with the cpu overhead of
  //   spinning, so we use SPIN_THRESHOLD_NANOS which is what AbstractQueuedSynchronizer uses for
  //   similar purposes.
  // * We want to behave reasonably for timeouts of 0

   * CharMatcher.is('a').replaceFrom("yaha", "oo")
   * }</pre>
   *
   * ... returns {@code "yoohoo"}.
   *
   * <p><b>Note:</b> If the replacement is a fixed string with only one character, you are better
   * off calling {@link #replaceFrom(CharSequence, char)} directly.
   *
   * @param sequence the character sequence to replace matching characters in