Return the concept of 'size' and 'empty' in class queue to the Container's, and introduce new concept 'size_in_byte' to represent the memory size occupied by the queue.

Make force_shutdown and graceful_shutdown be able to reconnect the server even if the link has broken.

Export some typedefs in container to class queue.

Optimize class queue.

Explicitly require the first parameter to be rvalue reference for i_packer::pack_msg(container_type&&, container_type&).

Promote queue's performance.