WebUtility.HtmlDecode replacement in .NET Core

This is in the System.Net.WebUtility class (Since .NET Standard 1.0) :

//
// Summary:
//     Provides methods for encoding and decoding URLs when processing Web requests.
public static class WebUtility
{
    public static string HtmlDecode(string value);
    public static string HtmlEncode(string value);
    public static string UrlDecode(string encodedValue);
    public static byte[] UrlDecodeToBytes(byte[] encodedValue, int offset, int count);
    public static string UrlEncode(string value);
    public static byte[] UrlEncodeToBytes(byte[] value, int offset, int count);
}