Async wait from asio steady timer

asio_async_wait.cpp

#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <iostream>

namespace asio = boost::asio;

void bind_handler(const boost::system::error_code& ec, asio::steady_timer& t, int count, int instance_tag)
{
  if (!ec) {
    if (count > 0) {
      std::cout << "instance " << instance_tag << " getting " << count << "\n";
      auto num_of_canceled = t.expires_at(t.expiry() + std::chrono::seconds(1));
      if (num_of_canceled) {
        std::cout << "instance " << instance_tag << " canceled "
                  << num_of_canceled << " await operations\n";
      }
      t.async_wait(boost::bind(bind_handler,
          asio::placeholders::error, boost::ref(t), --count, instance_tag));
    }
  }
  else if (ec == asio::error::operation_aborted) {
    std::cout << ec.message() << std::endl;
  }
  else
    std::cout << "You shouldn't see this line\n";
  std::cout << "-------------done-------------------\n";
}


int main()
{
  asio::io_context io_context(1);
  asio::steady_timer t(io_context, std::chrono::seconds(1));

  int count = 20;

  int instance_1 = 1;
  int instance_2 = 2;

  t.async_wait(boost::bind(bind_handler, asio::placeholders::error, boost::ref(t), count, instance_1));
  t.async_wait(boost::bind(bind_handler, asio::placeholders::error, boost::ref(t), count, instance_2));

  io_context.run();

  return 0;

}