if (log.isDebugEnabled()) {
                    log.debug("Have intermediate reply " + response);
                }

                if (first) {
                    final int credit = resp.getCredit();
                    if (log.isDebugEnabled()) {
                        log.debug("Credit from intermediate " + credit);
                    }
                    this.credits.release(credit);

   * array whose contents are initially non-null. The {@code @Nullable} annotation indicates that
   * this method will write nulls into the array during iteration.
   *
   * <p>This is mainly just to avoid the intermediate ArrayDeque in ConsumingQueueIterator.
   */
  private static <I extends Iterator<?>> Iterator<I> consumingForArray(@Nullable I... elements) {
    return new UnmodifiableIterator<I>() {
      int index = 0;