本程序适用于低功耗蓝牙，用于server，和 client端连接上之后，可以互发数据，实现数据的传输(This file is for gatt server. It can send adv data, be connected by clent Client demo will enable gatt_server's notify after connection. Then two devices will exchange data.)

本程序用于ESP32 蓝牙模块的断电重连，在连接成功因为对端模块 断电，故障，自模块，可以在对端上电之后，自动连接，不需重新设置(This program is used for the ESP32 Bluetooth module's power failure reconnection. The connection is successful, because the terminal module is power-off, and the fault is self module. I