### Question:
ConnectPool implements Closeable { List<Connection> shouldHeartbeat() { final List<Connection> heartbeats = new ArrayList<>(); for (Connection conn : conns) { if (conn.shouldHeartbeat()) { heartbeats.add(conn); } } return heartbeats; } ConnectPool(final NettyClientConfig config, final String address, final Bootstrap bootstrap, final EventBus eventBus); @Override void close();  }### Answer:
@Test public void checkHeartbeatSizeTest() { try { Thread.sleep(HEARTBEATINTERVAL + 100); } catch (InterruptedException e) { logger.error(e.getMessage(), e); } List<Connection> list = pool.shouldHeartbeat(); Assert.assertEquals(POOLSIZE, list.size()); }