Forward a preference to the underlying executor.

template<
    typename Property>
constraint_t< can_prefer< const Executor &, Property >::value &&!is_convertible< Property, execution::blocking_t::always_t >::value, strand< decay_t< prefer_result_t< const Executor &, Property > > > > prefer(
    const Property & p) const;

Do not call this function directly. It is intended for use with the prefer customisation point.

For example:

boost::asio::strand<my_executor_type> ex1 = ...;
auto ex2 = boost::asio::prefer(ex1,
    boost::asio::execution::blocking.never);