code: @Nonnull
    public final UnifiedResponse setStrictTransportSecurity (final int nMaxAgeSeconds, final boolean bIncludeSubdomains)
    {
      setCustomResponseHeader (CHttpHeader.STRICT_TRANSPORT_SECURITY,
                               new CacheControlBuilder ().setMaxAgeSeconds (nMaxAgeSeconds).getAsHTTPHeaderValue () +
                                                                      (bIncludeSubdomains ? ";" +
                                                                                            CHttpHeader.VALUE_INCLUDE_SUBDOMAINS
                                                                                          : ""));
      return this;
    }
docs: When specifying <code>false</code>, this method uses a special response
  header to prevent certain browsers from MIME-sniffing a response away from
  the declared content-type. When passing <code>true</code>, that header is
  removed.
  
  @param nMaxAgeSeconds
  number of seconds, after the reception of the STS header field,
  during which the UA regards the host (from whom the message was
  received) as a Known HSTS Host.
  @param bIncludeSubdomains
  if enabled, this signals the UA that the HSTS Policy applies to this
  HSTS Host as well as any sub-domains of the host's domain name.
  @return this