Each actor executes a user-provided function on a simulated |Host|_
with which it can interact. Communications are not directly sent to
actors, but posted onto a |Mailbox|_ that serve as rendez-vous point
Each actor executes a user-provided function on a simulated |Host|_
with which it can interact. Communications are not directly sent to
actors, but posted onto a |Mailbox|_ that serve as rendez-vous point