Immutable.Record instances should not be boxed

[Gozala]

I have being running into a dropped missing unique "key" prop issue with Immutable.Record instances as they are boxed, I have posted a comment in the relevant change:
6d8b850#commitcomment-10791363

I there a reason why Immutable instances are also boxed and not just cursors ?

Also regardless of type of the structure that omniscient boxes it should probably use a key from that structure otherwise it is impossible to render data structure of that type with a key.

[mikaelbr]

Immutable instances are boxed to unwrap them as arguments when passed to the render-function but still work as expected inside the shouldComponentUpdate.

You may have a point about using the key from the structure which is passed. For now it only checks the argument key or props.key. If we were to extend this, we would have to do some "precedence checking". What if argument key is set, and we have this:

if (_isCursor(props) || _isImmutable(props)) {
  inputCursor = props;
  _props = {};
  _props[_hiddenCursorField] = inputCursor;
}

if (inputCursor && inputCursor.get('key')) {
  key = inputCursor.get('key');
}

This would override key, passed in as argument, but that should probably have higher precedence. So we would have to do

if (!key && inputCursor && inputCursor.get('key')) {
  key = inputCursor.get('key');
}

But in this way we are starting to more and more couple to the Immutable.js implementation. _isCursor and _isImmutable are overridables, but inputCursor.get('key') would be implementation specific.