Flush data from the cache at a given cache key. If the data is not held by the cache, or is already expired, then this method is a no-op; otherwise, the data is removed from the cache.
Cache flush requests may take some time to process. As a good rule of thumb, the cache should be considered in-sync within 30 seconds of issuing a
CacheFlush request. All cache flush requests must be authorized either by a Buildless API key, or a user token.