Training a model should progressively log its progress

[JasonShin]

• I'm submitting a ...
  [/] feature request

• Summary
  I'm thinking we can expose something like

const clusters = kmean.fit({
   X: [[1, 2], [1, 4], [1, 0], [4, 2], [4, 4], [4, 0]],
   log: function(msg) {
     // msg contains the details about the training progress
   }
 });

Considerations:

• Enable it optionally

[efritsche69]

Question: is this feature allready implemented or under delvelopment?