android/guava/src/com/google/common/cache/CacheLoader.java
public static <K, V> CacheLoader<K, V> from(Function<K, V> function) {
    return new FunctionToCacheLoader<>(function);
  }
public static <K, V> CacheLoader<K, V> from(Function<K, V> function) {
    return new FunctionToCacheLoader<>(function);
  }
Returns a cache loader that uses {@code function} to load keys, and without supporting either
reloading or bulk loading. This is most useful when you can pass a lambda expression. Otherwise
it is useful mostly when you already have an existing function instance.

@param function the function to be used for loading values; must never return {@code null}
@return a cache loader that loads values by passing each key to {@code function}