Obtain an executor with the specified allocator property.

template<
    typename OtherAllocator>
basic_system_executor< Blocking, Relationship, OtherAllocator > require(
    execution::allocator_t< OtherAllocator > a) const;

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

For example:

boost::asio::system_executor ex1;
auto ex2 = boost::asio::require(ex1,
    boost::asio::execution::allocator(my_allocator));