How to monitor the progress of training a classifier?

I've had p = Predict[x -> y] running for hours and I have now idea if I should kill it or not.

I'm looking for some rough bounds for an estimate of how long Predict[] or Classify[] will take to train depending on the size of the input and the method used:

• "LinearRegression"
• "NearestNeighbors"
• "RandomForest"
• "NeuralNetwork"

Would be really helpful to monitor the loss function like you can in other ML systems.