MeshLineUpdate

        void Update ()
        {
            var mesh = Application.isPlaying ? _meshFilter.mesh : _meshFilter.sharedMesh;

            var uv = mesh.uv;

            var colors = new Color[uv.Length];

            for (var i = 0; i < uv.Length; i++)
            {
                if (From <= 0)
                {
                    colors[i] = ColorB;
                }
                else
                {
                    var proc = (float) i / uv.Length;
                    if (proc < From)
                    {
                        colors[i] = ColorA;
                    }
                    else if (proc < From + FromDelay)
                    {
                        var start = proc - From;
                        var diffPr = start / FromDelay;
                        colors[i] = Color.Lerp( ColorA, ColorB, diffPr);
                    }
                    else
                    {
                        colors[i] = ColorB;
                    }
                }
            }

            mesh.colors = colors;
        }