Sets the description of the type of cache being used.

The value should not include particulars about the cache; only a human friendly description of the kind of cache. For example, instead of "HTTP @ https://some/cache" it should be just "HTTP". Particular configuration should be set via config.

BuildCacheServiceFactory implementations should always return the same value for the same cache “type”. All implementations should call this method.

Values should be lowercase, except where using an acronym (e.g. HTTP).

Subsequent calls to this method replace the previously set value.