Realtime channel initial value on channel creation

t would be advantageous to dispatch an initial data packet to the client upon the creation of a new real-time channel.

At present, to access a real-time data stream, one must initially fetch certain information using the REST API, followed by establishing a real-time channel to receive ongoing updates.

By transmitting the initial value of the selected data through the real-time channel, we can position Supabase as a viable alternative to Firebase.