taskA                                                                              
                                                                                                                       
                                                                                                                       
                                                                               dataaaa                                 
                                                                                                                       
                                                                                                                       
                   OK                              check                                                       NG      
                                                                                                                       
                                                                                                                       
                                                                                                                       
                                                                                                                       
                                                                                                                       
                                                                                                                       
                                                                                                                       
                                                                                                                   true
                                              retry?                                                                   
                                                                               false