* Often called multiple times (that is, both when the inputs complete and when the output
   * completes).
   *
   * <p>This is similar to our proposed {@code afterCommit} method but not quite the same. See the
   * description of CL 265462958.
   */
  // TODO(user): Write more tests for memory retention.
  @ForOverride
  @OverridingMethodsMustInvokeSuper