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### Move accept token requirements

A move accept token is a completion token for completion signature `void(error_code, typename Protocol::socket)` or completion signature `void(error_code, typename Protocol::socket::template rebind_executor<Executor>::other)`, for the type `Protocol` of the acceptor class template.

##### Examples

A free function as a move accept token:

    void accept_handler(
        const boost::system::error_code& ec, boost::asio::ip::tcp::socket s)
    {
      ...
    }

A move accept token function object:

    struct accept_handler
    {
      ...
      void operator()(
          const boost::system::error_code& ec, boost::asio::ip::tcp::socket s)
      {
        ...
      }
      ...
    };

A lambda as a move accept token:

    acceptor.async_accept(...,
        [](const boost::system::error_code& ec, boost::asio::ip::tcp::socket s)
        {
          ...
        });

A non-static class member function adapted to a move accept token using `std::bind()`:

    void my_class::accept_handler(
        const boost::system::error_code& ec, boost::asio::ip::tcp::socket socket)
    {
      ...
    }
    ...
    boost::asio::async_accept(...,
        std::bind(&my_class::accept_handler,
          this, std::placeholders::_1,
          std::placeholders::_2));

Using use_future as a move accept token:

    std::future<boost::asio::ip::tcp::socket> f =
      acceptor.async_accept(..., boost::asio::use_future);
    ...
    try
    {
      boost::asio::ip::tcp::socket s = f.get();
      ...
    }
    catch (const system_error& e)
    {
      ...
    }

Using use_awaitable as a move accept token:

    boost::asio::awaitable<void> my_coroutine()
    {
      try
      {
        ...
        boost::asio::ip::tcp::socket s =
          co_await acceptor.async_accept(
              ..., boost::asio::use_awaitable);
        ...
      }
      catch (const system_error& e)
      {
        ...
      }
    }