如何遍历boost::variant<std::vector<int>，std::vector<String>>？

#include <boost/variant.hpp>
#include <iostream>
#include <vector>
#include <string>

typedef std::vector<int> IntVector;
typedef std::vector<std::string> StringVector;
typedef boost::variant<IntVector, StringVector> VariantType;

class VariantVisitor : public boost::static_visitor<>
{
public:
    void operator()(IntVector& vec) const
    {
        for (const auto& value : vec)
        {
            std::cout << value << std::endl;
        }
    }

    void operator()(StringVector& vec) const
    {
        for (const auto& value : vec)
        {
            std::cout << value << std::endl;
        }
    }
};

int main()
{
    VariantType variant;
    variant = IntVector{1, 2, 3, 4, 5}; // 或者 variant = StringVector{"a", "b", "c"};

    VariantVisitor visitor;
    boost::apply_visitor(visitor, variant);

    return 0;
}