CoreMLUpdateTask.swift

let modelConfig = MLModelConfiguration()
modelConfig.computeUnits = .cpuAndGPU

let updateTask = try MLUpdateTask(forModelAt: modelURL, trainingData: batchProvider(), configuration: modelConfig,
                             progressHandlers: MLUpdateProgressHandlers(forEvents: [.trainingBegin,.epochEnd],
                              progressHandler: { (contextProgress) in
                                print(contextProgress.event)
                             }) { (finalContext) in
                                
                                if finalContext.task.error?.localizedDescription == nil
                                {
                                    let fileManager = FileManager.default
                                    do {

                                        let documentDirectory = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor:nil, create:true)
                                        let fileURL = documentDirectory.appendingPathComponent("CatDog.mlmodelc")
                                        try finalContext.model.write(to: fileURL)
                                        
                                        self.updatableModel = self.loadModel(url: fileURL)

                                    } catch(let error) {
                                        print("error is \(error.localizedDescription)")
                                    }
                                }
                                
                                
            })
            
 updateTask.resume()