code: public <V> EntryStream<T, V> mapToEntry(Function<? super T, ? extends V> valueMapper) {
          return new EntryStream<>(stream().map(e -> new SimpleImmutableEntry<>(e, valueMapper.apply(e))), context);
      }
docs: Returns an {@link EntryStream} consisting of the {@link Entry} objects
  which keys are elements of this stream and values are results of applying
  the given function to the elements of this stream.
  
  <p>
  This is an <a href="package-summary.html#StreamOps">intermediate</a>
  operation.
  
  @param <V> The {@code Entry} value type
  @param valueMapper a non-interfering, stateless function to apply to each
  element
  @return the new stream