Does relay Wait for the WebSocket connection to be open, before sending a message ?

Hello,
I'm not sure relay js handles this or not, suppose we render application and we have few subscriptions to execute, but when they execute
the websocket is trying to connect, and eventually it connects, after app is rendered, what happen to executed subscriptions before websocket link is established ?
expected behavior is for every subscription executed before websocket link is ready, relay wait, and send subscribe message, after websocket link is established.