Hi @me-supachai okay thanks for the clarification.
The stream engine API is not designed to work in conjunction with the Unity SDK so you will need to choose one or the other for your blink detection. As previously stated, if you use the Unity SDK, you will only be able to detect validity on both eyes captured which could still be used theoretically to capture blinks by creating a custom loop timer (of around 300-400ms) though this technique will be less reliable than if you have both eye validitys exposed and can introduce a more sophisticated algorithm for blink detection.
So long as your intention is for interaction, then you should not need worry about the analytical licence. We would recommend first trying with Unity a simple loop counter and let us know if you think it’s accurate enough for your needs.