code: public static HttpParameters wrap(HttpParameters wrapped) {
  		// null remains null
  		if(wrapped == null) return null;
  		// Empty are unmodifiable
  		if(wrapped == EmptyParameters.getInstance()) return wrapped;
  		// ServletRequest parameters are unmodifiable already
  		if(wrapped instanceof ServletRequestParameters) return wrapped;
  		// Already wrapped
  		if(wrapped instanceof UnmodifiableHttpParameters) return wrapped;
  		// Wrapping necessary
  		return new UnmodifiableHttpParameters(wrapped);
  	}
docs: Wraps the given parameters to ensure they are unmodifiable.
  
  @return  {@code null} when wrapped is {@code null}, otherwise unmodifiable parameters