∀ {α : Type w} {m : Type w → Type w'} {β : Type w} [inst : Std.Iterator α m β] {it : Std.IterM m β}
  {it' : Std.IterM m β},
  it.internalState.inner.IsPlausibleStep (Std.IterStep.skip it') →
    Std.Iterators.Types.Drop.PlausibleStep it (Std.IterStep.skip (Std.IterM.drop it.internalState.remaining it'))