public Builder addHiddenUnits(org.bwapi.proxy.messages.GameMessages.UnitId value) {
        if (hiddenUnitsBuilder_ == null) {
          if (value == null) {
            throw new NullPointerException();
          }
          ensureHiddenUnitsIsMutable();
          hiddenUnits_.add(value);
          onChanged();
        } else {
          hiddenUnitsBuilder_.addMessage(value);
        }
        return this;
      }