Pass cancellation token through to semaphore wait. Use null conditional operator for max age check.

Update unit test to allow for more derived type TaskCanceledException, which is thrown by the semaphore wait.

Author: cmpcdaly

FirebaseAdmin/FirebaseAdmin.Tests/Auth/FirebaseAuthTest.cs

@@ -136,7 +136,7 @@ public async Task VerifyIdTokenCancel()
             var canceller = new CancellationTokenSource();
             canceller.Cancel();
             var idToken = await FirebaseTokenVerifierTest.CreateTestTokenAsync();
-            await Assert.ThrowsAsync<OperationCanceledException>(
+            await Assert.ThrowsAnyAsync<OperationCanceledException>(
                 async () => await FirebaseAuth.DefaultInstance.VerifyIdTokenAsync(
                     idToken, canceller.Token));
         }

FirebaseAdmin/FirebaseAdmin/Auth/HttpPublicKeySource.cs

@@ -68,7 +68,7 @@ public async Task<IReadOnlyList<PublicKey>> GetPublicKeysAsync(
         {
             if (_cachedKeys == null || _clock.UtcNow >= _expirationTime)
             {
-                await _lock.WaitAsync().ConfigureAwait(false);
+                await _lock.WaitAsync(cancellationToken).ConfigureAwait(false);
 
                 try
                 {
@@ -83,7 +83,7 @@ public async Task<IReadOnlyList<PublicKey>> GetPublicKeysAsync(
                             _cachedKeys = ParseKeys(await response.Content.ReadAsStringAsync()
                                 .ConfigureAwait(false));
                             var cacheControl = response.Headers.CacheControl;
-                            if (cacheControl != null && cacheControl.MaxAge.HasValue)
+                            if (cacheControl?.MaxAge != null)
                             {
                                 _expirationTime = now.Add(cacheControl.MaxAge.Value)
                                     .Subtract(ClockSkew);