Method Current

tests/gtest/gtest.h:10725–10728

We need to use cached value referenced by iterator_ because *iterator_ can return a temporary object (and of type other then T), so just having "return &*iterator_;" doesn't work. value_ is updated here and not in Advance() because Advance() can advance iterator_ beyond the end of the range, and we cannot detect that fact. The client code, on the other hand, is responsible for not calling Current(

    // detect that fact. The client code, on the other hand, is
    // responsible for not calling Current() on an out-of-range iterator.
    const T* Current() const override {
      if (value_.get() == nullptr) value_.reset(new T(*iterator_));
      return value_.get();
    }
    bool Equals(const ParamIteratorInterface<T>& other) const override {
      // Having the same base generator guarantees that the other
      // iterator is of the same type and we can downcast.