/// <summary>
 /// List all the subscriptions under a specified topic.
 /// <see href="https://msdn.microsoft.com/en-us/library/azure/mt639400.aspx" />
 /// </summary>
 /// <param name='operations'>
 /// The operations group for this extension method.
 /// </param>
 /// <param name='nextPageLink'>
 /// The NextLink from the previous successful call to List operation.
 /// </param>
 /// <param name='cancellationToken'>
 /// The cancellation token.
 /// </param>
 public static async Task <IPage <SubscriptionInner> > ListByTopicNextAsync(this ISubscriptionsOperations operations, string nextPageLink, CancellationToken cancellationToken = default(CancellationToken))
 {
     using (var _result = await operations.ListByTopicNextWithHttpMessagesAsync(nextPageLink, null, cancellationToken).ConfigureAwait(false))
     {
         return(_result.Body);
     }
 }