This is a fork of the DFRobot library "DFRobot_Wifi_Bee_ESP8266" https://github.com/Arduinolibrary/DFRobot_Wifi_Bee_ESP8266
That orignal ESP library and the Core files of the DFRduino M0 Mainboard caused issues, now resolved by adjusting the core files: See for details: DFRobot/DFRobotDuinoBoard#2
This fork doesn't use the delay() function.