code: public Observable<Void> cancelAsync(String resourceGroupName, String serverName, String databaseName, UUID operationId) {
          return cancelWithServiceResponseAsync(resourceGroupName, serverName, databaseName, operationId).map(new Func1<ServiceResponse<Void>, Void>() {
              @Override
              public Void call(ServiceResponse<Void> response) {
                  return response.body();
              }
          });
      }
docs: Cancels the asynchronous operation on the database.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param serverName The name of the server.
  @param databaseName The name of the database.
  @param operationId The operation identifier.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.