### Question:
BiIteration { public final BiStream<L, R> iterate() { return BiStream.from(iteration.iterate()); }  final BiIteration<L, R> yield(L left, R right); final BiIteration<L, R> yield(Continuation continuation); final BiStream<L, R> iterate();  }### Answer:
@Test public void oneTimeIteration() { BiIteration<String, String> iteration = new BiIteration<>(); iteration.iterate(); assertThrows(IllegalStateException.class, iteration::iterate); }