Broadcast a message to all connected clients to a channel.
val channel = supabase.channel("room1")
channel.subscribe(blockUntilSubscribed = true)
channel.broadcast("cursor-pos", message = buildJsonObject \{
put("x", 10)
put("y", 20)
\})
val channel = supabase.channel("room1")
channel.broadcast("cursor-pos", message = buildJsonObject \{
put("x", 10)
put("y", 20)
\})