Initial processing of an update event.

he Nodes are placed in a Registry. They are retrieved by their Name field and are destroyed when removed from the Registry. When new update event arrives, the procedure searches for the destination Node and places it into theWaitingQueue. This is done so because accepting an event should be a fast operation and the full processing may require dependency tree walk. Repeated placement into WaitingQueue does not change anything. As long as the current copy of the dependency tree (one of the two) accepts the new events, the out-of-date Nodes await in the WaitingQueue. When the current tree stop accepting new events and start processing then the Nodes are extracted from theWaitingQueue and processed. Such procedure is described next.