Calculating length of a Span of bytes when encoding text [Answered]

    private Span<char> ToBase64(Span<char> text)
    {
        // _encoding is UTF-8
        
        // get how many bytes the text will take up when encoded
        var byteCount = _encoding.GetByteCount(text);
        
        // alloc array with that count so we can get a Span<byte>
        Span<byte> span = stackalloc byte[byteCount];
        
        // write the encoded text into the byte span
        _ = _encoding.GetBytes(text, span);
        
        // use the encoded byte span to actually go to base64
        // _encoder is a nuget package that asks for an ArraySegment<char>
        return _encoder.ToBaseNonAlloc(span.ToArray());
    }

    private Span<char> ToBase64(Span<char> text)
    {
        // _encoding is UTF-8
        
        // get how many bytes the text will take up when encoded
        var byteCount = _encoding.GetByteCount(text);
        
        // alloc array with that count so we can get a Span<byte>
        Span<byte> span = stackalloc byte[byteCount];
        
        // write the encoded text into the byte span
        _ = _encoding.GetBytes(text, span);
        
        // use the encoded byte span to actually go to base64
        // _encoder is a nuget package that asks for an ArraySegment<char>
        return _encoder.ToBaseNonAlloc(span.ToArray());
    }

    private class MyObject
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public bool Alive { get; set; }
    }
    
    [Fact]
    public void Encode_ShouldRoundTrip()
    {
        var obj = new MyObject
        {
            Name = "John Doe",
            Age = 32,
            Alive = true
        };

        var json = JsonConvert.SerializeObject(obj);

        // _encoder here is my own class where the above method lives
        var encoded = _encoder.Encode(json);
        var unencoded = _encoder.Decode(encoded);

        var newObj = JsonConvert.DeserializeObject<MyObject>(unencoded);

        newObj.Should().BeEquivalentTo(obj);
    }

    private class MyObject
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public bool Alive { get; set; }
    }
    
    [Fact]
    public void Encode_ShouldRoundTrip()
    {
        var obj = new MyObject
        {
            Name = "John Doe",
            Age = 32,
            Alive = true
        };

        var json = JsonConvert.SerializeObject(obj);

        // _encoder here is my own class where the above method lives
        var encoded = _encoder.Encode(json);
        var unencoded = _encoder.Decode(encoded);

        var newObj = JsonConvert.DeserializeObject<MyObject>(unencoded);

        newObj.Should().BeEquivalentTo(obj);
    }