List of available hooks:

ctx.hook.on_world_update()
ctx.hook.on_world_update_client()
ctx.hook.on_world_update_host()
ctx.hook.on_new_player_seen(new_playerdata, player_count) - called the first time player with this peer_id has entered the world
ctx.hook.on_local_player_spawn(my_player)
ctx.hook.on_client_spawned(peer_id, new_playerdata)
ctx.hook.on_should_send_updates() - called either when we connect, or somebody else connects (and sends "welcome" message)