Question about Pybamm solution

[YouHyin]

Hello, I want to plot discharge voltage curve though pybamm, by a long-time cycling simulation (1000 cycles)
https://github.com/pybamm-team/PyBaMM/blob/develop/examples/notebooks/simulating-long-experiments.ipynb

I want to draw a discharge curve for each cycle(ex. "10" cycle).
So I'm analyzing the code(https://github.com/pybamm-team/PyBaMM/blob/develop/pybamm/simulation.py)

        if starting_solution is None:
            starting_solution_cycles = []
            starting_solution_summary_variables = []
            starting_solution_first_states = []
        elif not hasattr(starting_solution, "all_summary_variables"):
            (
                cycle_solution,
                cycle_sum_vars,
                cycle_first_state,
            ) = pybamm.make_cycle_solution(
                starting_solution.steps,
                esoh_solver=esoh_solver,
                save_this_cycle=True,
            )
            starting_solution_cycles = [cycle_solution]
            starting_solution_summary_variables = [cycle_sum_vars]
            starting_solution_first_states = [cycle_first_state]
        else:
            starting_solution_cycles = starting_solution.cycles.copy()
            starting_solution_summary_variables = (
                starting_solution.all_summary_variables.copy()
            )
            starting_solution_first_states = (
                starting_solution.all_first_states.copy()
            )

        cycle_offset = len(starting_solution_cycles)
        all_cycle_solutions = starting_solution_cycles
        all_summary_variables = starting_solution_summary_variables
        all_first_states = starting_solution_first_states
        current_solution = starting_solution or pybamm.EmptySolution()

Question : What is the difference between [cycle_solution], [cycle_sum_vars], and [cycle_first_state] ?

Question2 : What is the difference between save_at_cycles and solution.all_first_states? (#2250)