code: public <K, V> EntryStream<K, V> mapToEntry(DoubleFunction<? extends K> keyMapper,
              DoubleFunction<? extends V> valueMapper) {
          return new EntryStream<>(stream().mapToObj(t -> new AbstractMap.SimpleImmutableEntry<>(keyMapper.apply(t),
                  valueMapper.apply(t))), context);
      }
docs: Returns an {@link EntryStream} consisting of the {@link Entry} objects
  which keys and values are results of applying the given functions to the
  elements of this stream.
  
  <p>
  This is an intermediate operation.
  
  @param <K> The {@code Entry} key type
  @param <V> The {@code Entry} value type
  @param keyMapper a non-interfering, stateless function to apply to each
  element
  @param valueMapper a non-interfering, stateless function to apply to each
  element
  @return the new stream
  @since 0.3.1