I am using Simple_observer example for listening the advertisement and using modified simple broadcaster example to advertise data. i am updating advertising packet every 10 sec in my simple broadcaster. i want to read that data on my simple_observer side. what changes do i need to make in my simple observer code. also i want to add a filter to read only advertising data of specific ble adresses(4 devices) instead of reading data from all, how can i achieve this?