...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Adapt a completion token to specify that the completion handler arguments should be combined into a single tuple argument.
template< typename CompletionToken> cancel_after_t< decay_t< CompletionToken >, Clock, WaitTraits > operator()( CompletionToken && completion_token) const;