private CommandMessage createLoginCommandMessage() {
CommandMessage commandMessage = new CommandMessage();
commandMessage.setOperation(CommandMessage.LOGIN_OPERATION);
String credString = username + ":" + password;
Encoder encoder = new Encoder(credString.length());
encoder.encode(credString.getBytes());
commandMessage.setBody(encoder.drain());
commandMessage.setDestination(DESTINATION);
return commandMessage;
}