code: public void setObserver(Map<String, Object> observer) {
          removeEntriesStartingWith(OBSERVER);
          eventMap.putAll(observer);
      }
docs: Set the observer keys/values. The provided Map will completely replace
  the existing observer, i.e. all current observer keys/values will be removed
  and the new observer keys/values will be added.
  
  @param observer - Map of all the observer keys/values