text: #pragma once
  
  #include <thread>
  #include <memory>
  #include <forward_list>
  #include "Export.h"
  #include "Span.h"
  #include "span_impl.h"
  #if defined(WIN32)
  #pragma warning( push )
  #pragma warning (disable : 4251)
  #endif
  
  namespace cppkin
  {
      class SpanContainer
      {
      public:
          static SpanContainer& Instance();
          ~SpanContainer();
          void PushSpan(Span& span);
          Span& TopSpan();
          void PopSpan();
          bool IsEmpty();
       private:
          SpanContainer();
  
      private:
          std::forward_list<Span*> m_spans;
      };
  }
  #if defined(WIN32)
  #pragma warning( pop )
  #endif