code: public ServiceFuture<List<DeletedCertificateItem>> getDeletedCertificatesNextAsync(final String nextPageLink, final ServiceFuture<List<DeletedCertificateItem>> serviceFuture, final ListOperationCallback<DeletedCertificateItem> serviceCallback) {
          return AzureServiceFuture.fromPageResponse(
              getDeletedCertificatesNextSinglePageAsync(nextPageLink),
              new Func1<String, Observable<ServiceResponse<Page<DeletedCertificateItem>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<DeletedCertificateItem>>> call(String nextPageLink) {
                      return getDeletedCertificatesNextSinglePageAsync(nextPageLink);
                  }
              },
              serviceCallback);
      }
docs: Lists the deleted certificates in the specified vault currently available for recovery.
  The GetDeletedCertificates operation retrieves the certificates in the current vault which are in a deleted state and ready for recovery or purging. This operation includes deletion-specific information. This operation requires the certificates/get/list permission. This operation can only be enabled on soft-delete enabled vaults.
  
  @param nextPageLink The NextLink from the previous successful call to List operation.
  @param serviceFuture the ServiceFuture object tracking the Retrofit calls
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object