...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Completion token type used to specify that the completion handler arguments should be passed additional values after the results of the operation.
template< typename CompletionToken, typename... Values> constexpr append_t< decay_t< CompletionToken >, decay_t< Values >... > append( CompletionToken && completion_token, Values &&... values);
Header: boost/asio/append.hpp
Convenience header: boost/asio.hpp