Node.js net module does not recognize Chinese, Korean, and other double byte character

Question

When I use client.write in the net module, it only recognizes English, Numbers, and other ASCII symbols.

const net = require("net");
const server = net.createServer();

server.on('connection', function(client) {
    client.write('中文 한글');  // some double byte unicode characters
});

I tried to encode to CP949 or CP950 but it does not help.

The text I get:
Screenshot Link

It is not as the text I wrote in the code.