code: public Criteria example(T example, Attribute<T, ?>... usingAttributes) {
          return example(criteria(), example, usingAttributes);
      }
docs: A 'criteria by example' will be created using an example entity. It will use <code>eq</code> for comparing 'simple' attributes,
  for <code>oneToOne</code> associations the entity PK will be compared and for oneToMany association an <code>in</code> for comparing associated entities PKs.
  
  @param example         An entity whose attribute's value will be used for creating a criteria
  @param usingAttributes attributes from example entity to consider.
  @return A criteria restricted by example.
  @throws RuntimeException If no attribute is provided.