code: @Nonnull
    public final UnifiedResponse setContent (@Nonnull final byte [] aContent)
    {
      ValueEnforcer.notNull (aContent, "Content");
      return setContent (aContent, 0, aContent.length);
    }
docs: Set the response content. To return an empty response pass in a new empty
  array, but not <code>null</code>.
  
  @param aContent
  The content to be returned. Is <b>not</b> copied inside! May not be
  <code>null</code> but maybe empty.
  @return this