Janus is a computer programming language partially described by K. Kahn and Vijay A. Saraswat in the paper "Actors as a special case of concurrent constraint (logic) programming" in 1990.
The logic of the bag channels produces a property shared by the actor model, namely that the order of arrival of the messages is not guaranteed.
This ability to pass mailboxes around and hold more than one is inherited in computer programming language ToonTalk, which is influenced by Janus.
The asker and teller aspects can be passed around as arguments independently of each other.
The syntax of the language prevents copying a teller or exercising it more than once.