Function apply_selectors 

pub fn apply_selectors(
    instrument: InstrumentType,
    params: &mut [f32],
    stored: &[SessionSelector],
) -> Vec<(usize, usize, usize)>

Point the selectors in params at the positions the session stored.

Returns the entries that could not be restored exactly, as (parameter, wanted, given) — a bank that has shrunk since the session was written has nothing at the far end of it any more, and the nearest thing to what the player chose is its last entry. Anything the instrument does not call a selector is ignored rather than written blind.