OfframpClientImpl implements OfframpClient<T> { @Override public void close() throws Exception { socket.close(); } OfframpClientImpl(OfframpOptions<T> options);   OfframpClientImpl(
      OfframpOptions<T> options,
      WebSocket.Factory socketFactory,
      CommitHandler.Factory commitHandlerFactory); @Override Publisher<Message<T>> messages(); @Override Mono<Boolean> commit(Map<Integer, Long> offsets); @Override Publisher<Set<Integer>> rebalances(); @Override void close();  }
@Test public void close() throws Exception { underTest.close(); verify(socket).close(); }