#include <boost/system/error_code.hpp>
#include <boost/asio/async_result.hpp>
#include <boost/asio/detail/handler_type_requirements.hpp>

template<
	class ReadHandler>
BOOST_ASIO_INITFN_RESULT_TYPE(
		ReadHandler, void(boost::system::error_code, std::size_t))
	async_read(ReadHandler&& handler)
{
	// If you get an error on the following line it means that your handler does
	// not meet the documented type requirements for a ReadHandler.
	BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;

	boost::asio::async_completion<ReadHandler,
		void(boost::system::error_code, std::size_t)> init(handler);
	return init.result.get();
}