module type MBOX = sig .. end
The type of mailboxes mbox with messages of type t
type 
The type of messages
type 
The type of the mailboxes
val create : string -> mbox
Creates a new mailbox with the passed name, or opens an existing
        mailbox. Names are global to the whole Netplex process system.
val send : mbox -> t -> unit
Send a message to this box. If the box is full, it is waited until
        the box is free again. If several senders wait for the box, one
        sender is selected.
val receive : mbox -> t
Receive a message: It is waited until a sender puts a message into
        the box. If several receivers wait for the box, one receiver is
        selected.