#### experimental::make_parallel_group (3 of 3 overloads)

Create a group of operations that may be launched in parallel.

    template<
        typename Allocator,
        typename Range>
    ranged_parallel_group< decay_t< Range >, Allocator > make_parallel_group(
        allocator_arg_t ,
        const Allocator & allocator,
        Range && range,
        constraint_t< is_async_operation_range< decay_t< Range > >::value >  = 0);

###### Parameters

allocator

  Specifies the allocator to be used with the result vectors.

range

  A range containing the operations to be launched.

For example:

    using op_type =
      decltype(socket1.async_read_some(asio::buffer(data1)));

    std::vector<op_type> ops;
    ops.push_back(socket1.async_read_some(asio::buffer(data1)));
    ops.push_back(socket2.async_read_some(asio::buffer(data2)));

    asio::experimental::make_parallel_group(
        std::allocator_arg_t,
        my_allocator,
        ops
      ).async_wait(
        asio::experimental::wait_for_all(),
        [](
            std::vector<std::size_t> completion_order,
            std::vector<std::error_code> e,
            std::vector<std::size_t> n
          )
        {
          for (std::size_t i = 0; i < completion_order.size(); ++i)
          {
            std::size_t idx = completion_order[i];
            std::cout << "socket " << idx << " finished: ";
            std::cout << e[idx] << ", " << n[idx] << "\n";
          }
        }
      );