How can I convert string to utf8 in Dart?

I am using aqueduct web api framework to support my flutter app. In my api backend I need to connect local network socket services. My problem is that I can't return the exact string (in tr). So, How can I convert string to utf8 in Dart?

Example:

@httpGet
Future<Response> getLogin() async {
    Socket.connect('192.168.1.22', 1024).then((socket) async {
    socket.listen((data) {
        // Expected return is: 1:_:2:_:175997:_:NİYAZİ TOROS
        print(new String.fromCharCodes(data).trim());
        xResult = new String.fromCharCodes(data).trim();
        print("xResult: $xResult");
    }, onDone: () {
        print("Done");
        socket.destroy();
    });

    socket.write('Q101:_:49785:_:x\r\n');
    });

    return new Response.ok(xResult);
}

The return is not in TR-tr language format.

Return text looks like:

**1:_:2:_:175997:_:NÝYAZÝ TOROS**

Correct must be:

**1:_:2:_:175997:_:NİYAZİ TOROS**

UPDATE:

xResult = new String.fromCharCodes(data).trim();
print(xResult);
responseBody = xResult.transform(utf8.decoder);
print(responseBody);

I can print the xResult but cannot print the responseBody after trying convert to UTF8

Solution

import 'dart:convert' show utf8;

var encoded = utf8.encode('Lorem ipsum dolor sit amet, consetetur...');
var decoded = utf8.decode(encoded);

There are also encoder and decoder to be used with streams

File.openRead().transform(utf8.decoder).