// (in startSignal.await()), and the others waiting for that thread's result.
      while (thread.isAlive() && thread.getState() != Thread.State.WAITING) {
        Thread.yield();
      }
    }
    gettersStartedSignal.countDown();
    gettersComplete.await();

    List<Object> resultList = Lists.newArrayListWithExpectedSize(nThreads);
    for (int i = 0; i < nThreads; i++) {

      tmp[5 - i] = hex.charAt(c & 0xF);
      c = (char) (c >> 4);
    }
    return String.copyValueOf(tmp);
  }

  // Fast matchers

  /** A matcher for which precomputation will not yield any significant benefit. */
  abstract static class FastMatcher extends CharMatcher {

    @Override
    public final CharMatcher precomputed() {
      return this;
    }

    @Override