/// <summary>
 /// Adds a subscription key to the user.
 /// </summary>
 /// <param name='operations'>
 /// The operations group for this extension method.
 /// </param>
 /// <param name='azureRegion'>
 /// Supported Azure regions for Cognitive Services endpoints. Possible values
 /// include: 'westus', 'westeurope'
 /// </param>
 /// <param name='userSubscriptionCreateObject'>
 /// Subscription key object.
 /// </param>
 /// <param name='cancellationToken'>
 /// The cancellation token.
 /// </param>
 public static async Task AddSubscriptionKeyAsync(this IUser operations, AzureRegions azureRegion, UserSubscriptionCreateObject userSubscriptionCreateObject = default(UserSubscriptionCreateObject), CancellationToken cancellationToken = default(CancellationToken))
 {
     (await operations.AddSubscriptionKeyWithHttpMessagesAsync(azureRegion, userSubscriptionCreateObject, null, cancellationToken).ConfigureAwait(false)).Dispose();
 }