如何组织boost日志接收器的线程安全读取？

#include <boost/log/core.hpp>
#include <boost/log/trivial.hpp>
#include <boost/log/expressions.hpp>
#include <boost/log/utility/setup/file.hpp>
#include <boost/log/utility/setup/console.hpp>
#include <boost/log/sinks/sync_frontend.hpp>
#include <boost/log/sinks/text_file_backend.hpp>
#include <boost/log/sinks/text_ostream_backend.hpp>
#include <boost/log/sources/severity_logger.hpp>
#include <boost/log/sources/record_ostream.hpp>
#include <boost/thread.hpp>

// 定义全局的boost日志接收器对象
boost::log::sources::severity_logger<boost::log::trivial::severity_level> logger;

// 定义互斥锁
boost::mutex mtx;

// 初始化日志配置
void init_logging()
{
    // 设置日志文件输出
    boost::log::add_file_log(
        boost::log::keywords::file_name = "sample.log",
        boost::log::keywords::auto_flush = true
    );

    // 设置日志级别
    boost::log::core::get()->set_filter(
        boost::log::trivial::severity >= boost::log::trivial::info
    );

    // 设置日志输出到控制台
    boost::log::add_console_log(std::cout);
}

// 写入日志
void write_log(const std::string& message)
{
    // 获取互斥锁的所有权
    boost::lock_guard<boost::mutex> lock(mtx);

    // 写入日志消息
    BOOST_LOG_SEV(logger, boost::log::trivial::info) << message;
}

// 读取日志
void read_log()
{
    // 获取互斥锁的所有权
    boost::lock_guard<boost::mutex> lock(mtx);

    // 读取日志消息
    boost::log::record_view rec = logger.open_record(boost::log::keywords::severity = boost::log::trivial::info);
    if (rec)
    {
        boost::log::record_ostream strm(rec);
        strm << rec.message();
        strm.flush();
    }
}

int main()
{
    // 初始化日志配置
    init_logging();

    // 创建多个写入日志的线程
    boost::thread_group write_threads;
    for (int i = 0; i < 5; ++i)
    {
        write_threads.create_thread([i]() {
            write_log("Log message from thread " + std::to_string(i));
        });
    }

    // 创建多个读取日志的线程
    boost::thread_group read_threads;
    for (int i = 0; i < 3; ++i)
    {
        read_threads.create_thread(read_log);
    }

    // 等待所有线程结束
    write_threads.join_all();
    read_threads.join_all();

    return 0;
}