Fusillade failing once cancelled

SampleTest.cs

using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using Fusillade;
using NUnit.Framework;
using Refit;

namespace FusilladeTests
{
	public interface ISampleApi
	{
		[Get ("/countryCodeJSON?formatted=true&lat=47.03&lng=10.2&username=demo&style=full")]
		Task<CountryCode> GetCountryCode (CancellationToken token = default (CancellationToken));
	}

	public class CountryCode
	{
		public string languages { get; set; }
		public string distance { get; set; }
		public string countryCode { get; set; }
		public string countryName { get; set; }
	}

	[TestFixture]
	public class Fusillade
	{
		ISampleApi api;

		[SetUp]
		public void Setup ()
		{
			var rateLimitedHandler = new RateLimitedHttpMessageHandler (new HttpClientHandler(), Priority.UserInitiated);
			var client = new HttpClient (rateLimitedHandler) {
				BaseAddress = new Uri ("http://api.geonames.org")
			};
			api = RestService.For<ISampleApi> (client);
		}

		// This should pass just fine (note how it is the exact same as the third item)
		[Test]
		public async Task Fusillade_Cancel_First ()
		{
			var result = await api.GetCountryCode ();
			Assert.NotNull (result);
		}

		// This should also pass just fine, but now all subsequent requests hang
		[Test]
		public void Fusillade_Cancel_Second ()
		{
			var cts = new CancellationTokenSource ();
			cts.Cancel ();
			Assert.ThrowsAsync<TaskCanceledException> (async () => await api.GetCountryCode (cts.Token));
		}

		// This _should_ pass, it is an exact copy of the first one above, but it just hangs
		[Test]
		public async Task Fusillade_Cancel_Third ()
		{
			var result = await api.GetCountryCode ();
			Assert.NotNull (result);
		}
	}
}