}
                        break;
                    } catch (final InterruptedException e) {
                        final InterruptedIOException ie = new InterruptedIOException("Interrupted while acquiring credits");
                        ie.initCause(e);
                        throw ie;
                    }
                } else {
                    // not enough credits available or too big, split

        runCleanup();
      }
    }

    /**
     * Performs routine cleanup prior to executing a write. This should be called every time a write
     * thread acquires the segment lock, immediately after acquiring the lock.
     */
    @GuardedBy("this")
    void preWriteCleanup() {
      runLockedCleanup();
    }

    void runCleanup() {
      runLockedCleanup();
    }

      Iterable<? extends ListenableFuture<? extends V>> futures) {
    return new FutureCombiner<>(false, ImmutableList.copyOf(futures));
  }

  /**
   * Creates a {@link FutureCombiner} requiring that all passed in futures are successful.
   *
   * <p>If any input fails, the returned future fails immediately.
   *
   * @since 20.0
   */
  @SafeVarargs