+ /*
+ * The graph's reference count is 0 if we're here. Increment
+ * it to avoid a double-destroy (possibly infinitely recursive)
+ * in this situation:
+ *
+ * 1. We put and destroy a connection.
+ * 2. This connection's destructor finalizes its active
+ * notification iterators.
+ * 3. A notification iterator's finalization function gets a
+ * new reference on its component (reference count goes from
+ * 0 to 1).
+ * 4. Since this component's reference count goes to 1, it takes
+ * a reference on its parent (this graph). This graph's
+ * reference count goes from 0 to 1.
+ * 5. The notification iterator's finalization function puts its
+ * component reference (reference count goes from 1 to 0).
+ * 6. Since this component's reference count goes from 1 to 0,
+ * it puts its parent (this graph). This graph's reference
+ * count goes from 1 to 0.
+ * 7. Since this graph's reference count goes from 1 to 0,
+ * its destructor is called (this function).
+ *
+ * With the incrementation below, the graph's reference count at
+ * step 4 goes from 1 to 2, and from 2 to 1 at step 6. This
+ * ensures that this function is not called two times.
+ */
+ obj->ref_count.count++;
+