+/* ACTIVE_CLIENTS
+ * An 'active' client is one that either
+ * - owns a lease, or
+ * - is requesting ownership of a lease (which will
+ * disconnect the current owner if granted)
+ *
+ * There can only be at most one of each kind of client at the same
+ * time. Any other client connections are queued in the
+ * listen() backlog, waiting to be accept()'ed.
+ */
+#define ACTIVE_CLIENTS 2
+