An OPEN message opens a connection to the server. The server will
respond to the OPEN message with an OPENED message.
An ADDC will add a connection to a pipe when given the name of the
remote pipe.
An ADDC will add a connection to an ACK when given
Q:ACK.
In response to a change in the server-side macro an ACK can be
sent to a given client.
If an ACK is sent from the server-side macro with null
as the remote connection, RMIF will broadcast the ACK to all
connected clients that are listening for the ACK.
(This is the most common form of ACK.)
When a client sends a SET to the server, the SET is
passed to the server-side macro. The server-side macro performs any necessary
validity checks (bounds checks, etc.) and, if the value is modified, it responds
by broadcasting the change with an ACK message.