Asio chat server example

Simple Asio chat server using WiFi STA or Ethernet.

Example workflow

Wi-Fi or Ethernet connection is established, and IP address is obtained.
Asio chat server is started on port number defined through the project configuration.
Chat server echoes a message (received from any client) to all connected clients.

Open project configuration menu (idf.py menuconfig) to configure Wi-Fi or Ethernet. See "Establishing Wi-Fi or Ethernet Connection" section in examples/protocols/README.md for more details.
Set server port number in menuconfig, "Example configuration".
Run idf.py -p PORT flash monitor to build and upload the example to your board and connect to it's serial terminal.
Wait for the board to connect to WiFi or Ethernet (note the IP address).
Connect to the server using multiple clients, for example using any option below.
- build and run asi chat client on your host machine
- run chat_client asio example on ESP platform
- since chat message consist of ascii size and message, it is possible to netcat nc IP PORT and type for example 4ABC<CR> to transmit 'ABC\n'

See the README.md file in the upper level 'examples' directory for more information about examples.