example create middleware in web api .Net 6

public class MyMiddleware
{
    private readonly RequestDelegate _next;
    public MyMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        var a = 1;
        var b = 2;
        var c = a + b;
        // do something with c
        
        await _next(context);
    }
}