public void close() {
try {
if (sessionKey != RexProMessage.EMPTY_SESSION) {
SessionRequestMessage sessionKillMessageToSend = new SessionRequestMessage();
sessionKillMessageToSend.metaSetKillSession(true);
sessionKillMessageToSend.setRequestAsUUID(UUID.randomUUID());
// need to set the session here so that the server knows which one to delete.
sessionKillMessageToSend.setSessionAsUUID(this.sessionKey);
final RexProMessage rcvMessage = sendRequest(sessionKillMessageToSend, 3);