能不能考虑 在vnpy/app/data_recorder/engine.py class RecorderEngine : close函数的最开头处，考虑增加K线收盘操作，保证郑交易最后一根K线能推入数据库中
def close(self):
for vt_symbol in self.bar_recordings:
bg = self.get_bar_generator(vt_symbol)
bg.generate()
self.active = False
if self.thread.isAlive():
self.thread.join()
