Василий Банников

using System;
using System.Linq;
using System.Text;

var originalString = "Lorem ipsum dolor sit amet. Мама мыла раму";
Console.WriteLine($"Original string: {originalString}");

var utf8Bytes = Encoding.UTF8.GetBytes(originalString);
var hexadecimalUtf8Bytes = ConvertBytesToHexString(utf8Bytes);
Console.WriteLine($"Hexadecimal bytes: {hexadecimalUtf8Bytes}");

var convertedBytes = ConvertHexStringToBytes(hexadecimalUtf8Bytes);
var convertedString = Encoding.UTF8.GetString(convertedBytes);
Console.WriteLine($"Decoded: {convertedString}");

static string ConvertBytesToHexString(byte[] bytes) =>
    BitConverter.ToString(bytes).Replace("-", "");

static byte[] ConvertHexStringToBytes(string hex) =>
    Enumerable.Range(0, hex.Length)
        .Where(x => x % 2 == 0)
        .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
        .ToArray();

Original string: Lorem ipsum dolor sit amet. Мама мыла раму
Hexadecimal bytes: 4C6F72656D20697073756D20646F6C6F722073697420616D65742E20D09CD0B0D0BCD0B020D0BCD18BD0BBD0B020D180D0B0D0BCD183
Decoded: Lorem ipsum dolor sit amet. Мама мыла раму

pub struct MimeType {
    extension: String,
    charset: String,
}

impl MimeType {
    pub fn new(extension: String, charset: String) -> MimeType {
        return MimeType { extension, charset };
    }

    pub fn extension(&self) -> &String {
        return &self.extension;
    }

    pub fn charset(&self) -> &String {
        return &self.charset;
    }
}