code: @Deprecated
    public FluoConfiguration addObserver(ObserverSpecification oconf) {
      int next = getNextObserverId();
      addObserver(oconf, next);
      return this;
    }
docs: Adds an {@link ObserverSpecification} to the configuration using a unique integer prefix that's
  not currently in use.
  
  @deprecated since 1.1.0. Replaced by {@link #setObserverProvider(String)} and
  {@link #getObserverProvider()}