code: public static <V> CacheLoader<Object, V> from(Supplier<V> supplier) {
      return new SupplierToCacheLoader<V>(supplier);
    }
docs: Returns a cache loader based on an <i>existing</i> supplier instance. Note that there's no need
  to create a <i>new</i> supplier just to pass it in here; just subclass {@code CacheLoader} and
  implement {@link #load load} instead.
  
  @param supplier the supplier to be used for loading values; must never return {@code null}
  @return a cache loader that loads values by calling {@link Supplier#get}, irrespective of the
  key