text: // Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
  // Distributed under the MIT License (http://opensource.org/licenses/MIT)
  
  #pragma once
  
  #include "spdlog/details/null_mutex.h"
  #include "spdlog/sinks/base_sink.h"
  #include "spdlog/details/synchronous_factory.h"
  
  #include <mutex>
  
  namespace spdlog {
  namespace sinks {
  
  template<typename Mutex>
  class null_sink : public base_sink<Mutex>
  {
  protected:
      void sink_it_(const details::log_msg &) override {}
      void flush_() override {}
  };
  
  using null_sink_mt = null_sink<details::null_mutex>;
  using null_sink_st = null_sink<details::null_mutex>;
  
  } // namespace sinks
  
  template<typename Factory = spdlog::synchronous_factory>
  inline std::shared_ptr<logger> null_logger_mt(const std::string &logger_name)
  {
      auto null_logger = Factory::template create<sinks::null_sink_mt>(logger_name);
      null_logger->set_level(level::off);
      return null_logger;
  }
  
  template<typename Factory = spdlog::synchronous_factory>
  inline std::shared_ptr<logger> null_logger_st(const std::string &logger_name)
  {
      auto null_logger = Factory::template create<sinks::null_sink_st>(logger_name);
      null_logger->set_level(level::off);
      return null_logger;
  }
  
  } // namespace spdlog
  