Listening for node/task events

[Steven F]

Is there a listener/technique for hooking into node events such as accepting/completing tasks? I'm attempting to track builds both as they start and end but also the beginning and end of their assignments to nodes. I see there is an ExecutorListener available, but it is not globally notified like other listeners. I don't see a way to leverage a RetentionStrategy to do what I'm trying to do.