public Builder addAgent(String nodeName) {
            if (agentNames.contains(nodeName)) {
                throw new RuntimeException("There is already an agent on node " + nodeName);
            }
            agentNames.add(nodeName);
            return this;
        }
Add a new trogdor agent node to the cluster.
trogdor/src/test/java/org/apache/kafka/trogdor/common/MiniTrogdorCluster.java