Manage state of chain with `StateManager` interface about faas-flow HOT 1 CLOSED

       chain.ApplyModifier(func (data []byte){ 
                        // save data  
                        fchain.GetContext.Set("beforecheck", data)
                        return data
                      }).Apply("func").ApplyModifier(func (data []byte){
                       // do some checking
                       // replay saved data 
                       return fchain.GetContext.Get("beforecheck") 
                      })