For only the second time since Drupal 8 went beta, no coding changes for the Optimizely module were needed for a new release of D8.
It's pretty amazing that a small module like this one, which uses only a very small subset of the API's, can reveal quite a few changes just by attempting to run through its normal functionality, its error checking, and automated tests.
Back in July of last year, I wrote about function cache_clear_all() being removed along with its wildcard for subpaths. At the time, I simply replaced that function with a clearing of the entire cache where any wildcard is used in the D7 version.
However, that cache invalidation must be re-written for Drupal 8 so that it works in a targeted manner and does not potentially cause such a big hit to performance.
Now that D8 has become much more stable, it's time I stopped procrastinating and do it right.