Obtain a polymorphic wrapper with the specified property.
template< typename Property> any_io_executor require( const Property & p, typename constraint< traits::require_member< const base_type &, const Property & >::is_valid >::type = 0) const; » more... template<> any_io_executor require( const execution::blocking_t::never_t & p, int ) const; » more... template< typename Property> any_executor require( Property ) const; » more...