Query the current value of the allocator property.

template<
    typename OtherAllocator>
constexpr Allocator query(
    execution::allocator_t< OtherAllocator > ) const;

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

For example:

auto ex = my_thread_pool.executor();
auto alloc = boost::asio::query(ex,
    boost::asio::execution::allocator);