Forward a preference to the underlying executor.

template<
    typename Property>
trampoline< decay_t< prefer_result_t< const Executor &, Property > >, Blocking, InlineExceptionHandling > prefer(
    const Property & p,
    constraint_t< can_prefer< const Executor &, Property >::value >  = 0,
    constraint_t< !is_identity_prefer< const Executor &, Property >::value >  = 0,
    constraint_t< !is_convertible< Property, execution::blocking_t >::value >  = 0,
    constraint_t< !is_convertible< Property, execution::relationship_t >::value >  = 0,
    constraint_t< !is_convertible< Property, execution::inline_exception_handling_t >::value >  = 0) const;

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