This works in .NET 8 but in .NET 4.8 the call to SendAsync does not return. What do I need to change? Thanks

using (var requestMessage = new HttpRequestMessage(HttpMethod.Get, url))
{
requestMessage.Headers.UserAgent.ParseAdd("test app");
requestMessage.Headers.Accept.ParseAdd("application/vnd.github.v3.raw");
requestMessage.Headers.Authorization = new AuthenticationHeaderValue("token", githubToken);
var httpClient = new HttpClient();
return await httpClient.SendAsync(requestMessage);
}