Drawing a line with Unity UI Toolkit

LineDrawer.cs

// Drawing a line with UITK https://forum.unity.com/threads/drawing-a-line-with-uitk.1193470/
public class LineDrawer : VisualElement
{
    private Vector3 startPos, endPos;
    private float thickness;

    public LineDrawer(Vector3 pos1, Vector3 pos2, float width)
    {
        startPos = pos1;
        endPos = pos2;
        thickness = width;

        generateVisualContent += OnGenerateVisualContent;
    }

    private void OnGenerateVisualContent(MeshGenerationContext ctx)
    {
        var angleDeg = Vector3.Angle(startPos, endPos);

        MeshWriteData mesh = ctx.Allocate(4, 6);
        Vertex[] vertices = new Vertex[4];
        vertices[0].position = startPos - new Vector3(0, thickness / 2, 0); //bottom left
        vertices[1].position = startPos + new Vector3(0, thickness / 2, 0); //top left
        vertices[2].position = endPos + new Vector3(0, thickness / 2, 0); //top right
        vertices[3].position = endPos - new Vector3(0, thickness / 2, 0); //bottom right

        for (var index = 0; index < vertices.Length; index++)
        {
            vertices[index].position += Vector3.forward * Vertex.nearZ;
            vertices[index].tint = Color.white;
        }

        mesh.SetAllVertices(vertices);
        mesh.SetAllIndices(new ushort[] { 0, 1, 3, 1, 2, 3 });
    }
}

public class CanvasManager : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        var doc = GetComponent<UIDocument>();
        doc.rootVisualElement.Add(new LineDrawer(new Vector2(20, 50), new Vector2(50, 50), 10));
    }
}