boost/asio/seq13: io executor

 // Wrap the (potentially polymorphic) executor so that we can bypass it when

    
 // dispatching on a target executor that has a native I/O implementation.
    
 template <typename Executor>
    
 class io_object_executor
    
 {
    
 public:
    
   io_object_executor(const Executor& ex,
    
       bool native_implementation) BOOST_ASIO_NOEXCEPT
    
     : executor_(ex),
    
       has_native_impl_(native_implementation)
    
   {
    
   }
    
  
    
   io_object_executor(const io_object_executor& other) BOOST_ASIO_NOEXCEPT
    
     : executor_(other.executo