public static AgentConfiguration getAgentConf() {
        if (agentConf == null) {
            synchronized (AgentConfiguration.class) {
                if (agentConf == null) {
                    agentConf = new AgentConfiguration();
                }
            }
        }
        return agentConf;
    }
singleton for agent configuration.

@return static instance of AgentConfiguration
inlong-agent/agent-common/src/main/java/org/apache/inlong/agent/conf/AgentConfiguration.java