如何在c++中绕过<<调用，就像"#ifndef DEBUG“宏一样？

#include <iostream>

class DebugStream {
private:
    std::string output;

public:
    DebugStream() {}
    ~DebugStream() {
        std::cout << output;
    }

    template <typename T>
    DebugStream& operator<<(const T& value) {
        output += std::to_string(value);
        return *this;
    }
};

// 使用示例
int main() {
    DebugStream debug;
    debug << "This is a debug message. " << 123 << std::endl;
    // 输出：This is a debug message. 123

    return 0;
}