FluxTraning log metrics

Dear All,
I am trying to use FluxTraing.jl to train my model:

traindata, valdata = splitobs((data_X, data_Yr))
trainiter, valiter = DataLoader(traindata, 128), DataLoader(valdata, 256);

learner = Learner(model, (trainiter, valiter), optim, lossfn, ToGPU(), Metrics(accuracy))

N_epochs = 500

FluxTraining.fit!(learner, N_epochs)

but I am not able to find a way how to log/save loss values during the training and validating phase.
Please could you help me?