Obtain a polymorphic wrapper with the specified property.

template<
    typename Property>
any_completion_executor require(
    const Property & p,
    typename constraint< traits::require_member< const base_type &, const Property & >::is_valid >::type  = 0) const;

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

For example:

any_completion_executor ex = ...;
auto ex2 = asio::require(ex, execution::relationship.fork);