// node_modules/react-native-background-timer/android/src/main/java/com/ocetnik/timer/BackgroundTimerModule.java

@ReactMethod
public void setTimeout(final int id, final double timeout) {
    Handler handler = new Handler();
    handler.postDelayed(new Runnable(){
        @Override
        public void run(){
            if (getReactApplicationContext().hasActiveCatalystInstance()) {
                getReactApplicationContext()
                    .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
                    .emit("backgroundTimer.timeout", id);
            }
       }
    }, (long) timeout);
}

// here
@ReactMethod
public void addListener(String eventName) {
  // Keep: Required for RN built in Event Emitter Calls.
}

// here
@ReactMethod
public void removeListeners(Integer count) {
  // Keep: Required for RN built in Event Emitter Calls.
}