code: public static DoubleStreamEx of(DoubleStream stream) {
          return stream instanceof DoubleStreamEx ? (DoubleStreamEx) stream
                  : new DoubleStreamEx(stream, StreamContext.of(stream));
      }
docs: Returns a {@code DoubleStreamEx} object which wraps given
  {@link DoubleStream}.
  
  <p>
  The supplied stream must not be consumed or closed when this method is
  called. No operation must be performed on the supplied stream after it's
  wrapped.
  
  @param stream original stream
  @return the wrapped stream
  @since 0.0.8