code: public EntryStream<V, K> invert() {
          return new EntryStream<>(stream().map(e -> new SimpleImmutableEntry<>(e.getValue(), e.getKey())), context);
      }
docs: Returns a stream consisting of the {@link Entry} objects which keys are
  the values of this stream elements and vice versa.
  
  <p>
  This is an <a href="package-summary.html#StreamOps">intermediate</a>
  operation.
  
  @return the new stream