[SuppressMessage(
    "Usage",
    "CA2234:Pass system uri objects instead of strings",
    Justification = "URL isn't passed as variable, but as literal.")]
private async Task<HttpResponseMessage> PostReservation(
    object reservation)
{

    using var factory =  new RestaurantApiFactory();

    var client = factory.CreateClient();

    string json = JsonSerializer.Serialize(reservation);
    using var content =  new StringContent(json);
    content.Headers.ContentType.MediaType = "application/json";
    return await client.PostAsync("reservations", content);
}