/** Cleans up resources to avoid excessive memory usage. */
public void cleanUp() {
topSnapshot.set(null);
singleMsgs.clear();
fullMsgs.clear();
rcvdIds.clear();
oldestNode.set(null);
partReleaseFut = null;
Collection<ClusterNode> rmtNodes = this.rmtNodes;
if (rmtNodes != null) rmtNodes.clear();
}
