code: public AzkabanClientStatus cancelFlow(String execId) throws AzkabanClientException {
      AzkabanMultiCallables.CancelFlowCallable callable =
          AzkabanMultiCallables.CancelFlowCallable.builder()
              .client(this)
              .execId(execId)
              .build();
  
      return runWithRetry(callable, AzkabanClientStatus.class);
    }
docs: Cancel a flow by execution id.