Removes all cache entries.
To only remove some cache entries, pass a URL pattern:
up.cache.clear('/users/*')
By default Unpoly automatically clears the entire cache whenever it processes
a request with an non-GET HTTP method. To customize this rule, use up.network.config.clearCache
.
The server may also clear the cache by sending an X-Up-Clear-Cache
header.
A URL pattern matching cache entries that should be cleared.
If omitted, the entire cache is cleared.