public ScanSettings.Builder setCallbackType(@CallbackType int callbackType) {

            if (!isValidCallbackType(callbackType)) {
                throw new IllegalArgumentException("invalid callback type - " + callbackType);
            }
            mCallbackType = callbackType;
            return this;
        }
Set callback type for Bluetooth LE scan.

@param callbackType The callback type flags for the scan.
@throws IllegalArgumentException If the {@code callbackType} is invalid.
rxandroidble/src/main/java/com/polidea/rxandroidble2/scan/ScanSettings.java