* @param max the upper bound (inclusive) of the range to constrain {@code value} to
   * @throws IllegalArgumentException if {@code min > max}
   * @since 21.0
   */
  public static long constrainToRange(long value, long min, long max) {
    checkArgument(min <= max, "min (%s) must be less than or equal to max (%s)", min, max);
    return Math.min(Math.max(value, min), max);
  }

  /**

   * Actually waiting for more than 219 years is not supported!
   */
  private static long toSafeNanos(long time, TimeUnit unit) {
    long timeoutNanos = unit.toNanos(time);
    return Longs.constrainToRange(timeoutNanos, 0L, (Long.MAX_VALUE / 4) * 3);
  }

  /**
   * Returns System.nanoTime() unless the timeout has already elapsed. Returns 0L if and only if the
   * timeout has already elapsed.
   */