Middleware for ASP.NET Core 3.1 WebAPI project to log response content size to app insights

ApiLoggingMiddleware.cs

public class ApiLoggingMiddleware
{
    private readonly RequestDelegate _next;

    public ApiLoggingMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        var originalBodyStream = context.Response.Body;

        using (var responseBody = new MemoryStream())
        {
            context.Response.Body = responseBody;
            await _next(context);


            // get app insights request telemetry for sdk
            var requestTelemetry = context.Features.Get<RequestTelemetry>();
            if (requestTelemetry != null)
            {
                // get the content size
                var contentSize = GetContentSize(context.Response);
                
                // append to the request telemetry
                requestTelemetry.Metrics.Add(new KeyValuePair<string, double>("Size", contentSize));
            }

            await responseBody.CopyToAsync(originalBodyStream);
        }
    }
    private long GetContentSize(HttpResponse response)
    {
        var size = response.Body.Length;

        // reset
        response.Body.Seek(0, SeekOrigin.Begin);

        return size;
    }
}