set method
Implementation
void set(String key, String log, {int limit: 200}) async {
SharedPreferences prefs = await SharedPreferences.getInstance();
List<String> oldLog = prefs.getStringList(key) ?? [];
oldLog.add(log.toString());
int oLen = oldLog.length;
if(oLen > limit) {
oldLog = oldLog.getRange(oLen - limit, oLen) as List<String>;
}
prefs.setStringList(key, oldLog);
}