code: @Deprecated // use withIdStrategy
      public JsonSet applyIdStrategy(IdStrategy strategy) {
          JsonSet newSet = new JsonSet();
          newSet.strategy = strategy;
          for (JsonElement e : this) {
              newSet.add(e);
          }
          return newSet;
      }
docs: May be used to change the contains behavior of the set. If set it will use the provided strategy to compare
  elements in the set instead of JsonElement.equals().
  
  Important: this creates a new set in order to remove duplicates.
  
  @param strategy
  an implementation of IdStrategy
  @return a new set with the elements of the old set, minus the duplicates.