Improve Mesh generation and rendering performance

Hello everyone,

since I just recently started looking into meshes, how they work, what they do and so on, I decided to use my own calculations to create a mesh of a circle. Unfortunately though, this is really, really slow! So I am looking for tips on improvements, to make it slow only (because that's probably the best it will get...)

Here is the code I use to generate a circle:

 public static void createCircle(MeshFilter meshFilter, float innerRadius, float outerRadius, Color color, float xPosition = 0, float yPosition = 0, float startDegree = 0, float endDegree = 360, int points = 100)
         {
             Mesh mesh = meshFilter.mesh;
             mesh.Clear();
             //These values will result in no (or very ugly in the case of points < 10) circle, so let's safe calculation and just return an empty mesh!
             if (startDegree == endDegree || points < 10 || innerRadius >= outerRadius || innerRadius < 0 || outerRadius <= 0)
             {
                 return;
             }
             //The points for the full circle shall be whatever is given but if its not the full circle we dont need all the points!
             points = (int)(Mathf.Abs(endDegree - startDegree) / 360f * points);
             //We always need an uneven number of points!
             if (points % 2 != 0) { points++; }
             Vector3[] vertices = new Vector3[points];
             float degreeStepSize = (endDegree - startDegree) * 2 / (points - 3);
             float halfRadStepSize = (degreeStepSize) * Mathf.Deg2Rad / 2f;
             float startRad = Mathf.Deg2Rad * startDegree;
             float endRad = Mathf.Deg2Rad * endDegree;
             //Let's save the vector at the beginning and the one on the end to make a perfectly straight line
             vertices[0] = new Vector3(Mathf.Sin(startRad) * outerRadius + xPosition, Mathf.Cos(startRad) * outerRadius + yPosition, 0);
             vertices[vertices.Length - 1] = new Vector3(Mathf.Sin(endRad) * innerRadius + xPosition, Mathf.Cos(endRad) * innerRadius + yPosition, 0);
             for (int i = 1; i < vertices.Length - 1; i++)
             {
                 //Pure coinsidence that saved some calculatons. Half Step Size is the same as what would needed to be calculated here!
                 float rad = (i - 1) * halfRadStepSize + startRad;
                 if (i % 2 == 0)
                 {
                     vertices[i] = new Vector3(Mathf.Sin(rad) * outerRadius + xPosition, Mathf.Cos(rad) * outerRadius + yPosition, 0);
                 }
                 else
                 {
                     vertices[i] = new Vector3(Mathf.Sin(rad) * innerRadius + xPosition, Mathf.Cos(rad) * innerRadius + yPosition, 0);
                 }
             }
             mesh.vertices = vertices;
 
             int[] tri = new int[(vertices.Length - 2) * 3];
             for (int i = 0; i < (vertices.Length - 2); i++)
             {
                 int index = i * 3;
                 if (i % 2 == 0)
                 {
                     tri[index + 0] = i + 0;
                     tri[index + 1] = i + 2;
                     tri[index + 2] = i + 1;
                 }
                 else
                 {
                     tri[index + 0] = i + 0;
                     tri[index + 1] = i + 1;
                     tri[index + 2] = i + 2;
                 }
             }
             mesh.triangles = tri;
             Vector3[] normals = new Vector3[vertices.Length];
             Color[] colors = new Color[vertices.Length];
             for (int i = 0; i < vertices.Length; i++)
             {
                 normals[i] = Vector3.forward;
                 colors[i] = color;
             }
             mesh.normals = normals;
             mesh.colors = colors;
 
             meshFilter.mesh = mesh;
         }
 

I know I "could just use the LineRenderer shipped with Unity, it is faster then anything you'll ever write", but that's not the point here. I am trying to understand meshes and see where I can tweak my code to improve it's performance

Thanks for your help in advance!