Should we send the observer an `x0` and `y0`?

[miguelgondu]

Now problem instances don't evaluate y0 eagerly. Should we keep the current interface for observers (i.e. sending it x0 and y0 at initalization)?

[miguelgondu]

Hi @SimonBartels! Feel free to close this issue if it has been addressed.

[SimonBartels]

Currently, nothing happens. The observer learns about y0 if the algorithm decides to evaluate x0.
I am tending to a solution where x0 is part of the problem information. What do you think?