title: How to get progress of current epoch during tf.keras training?
body: <p>I am writing a GUI application for training of various <code>tf.keras</code>-based models. So all the information on <code>accuracy</code>, <code>loss</code> etc. should be visible on the GUI instead of the default Keras console output.</p>
  
  <p>Now I managed to get all the relevant information during model training via a custom <code>tf.keras.callbacks.Callback</code> class, which works fine. But I also want to get the progress of the current epoch, i.e. how much % of the current epoch has been trained so far, i.e. what Keras prints to console during training via the progress bar.</p>
  
  <p>Is there any way to retrieve that information in a Keras callback as well?</p>