public static PipeConfigNodePluginAgent plugin() {
    return PipeConfigNodeAgentHolder.HANDLE.pipeConfigNodePluginAgent;
  }
Get the singleton instance of {@link PipeConfigNodePluginAgent}.

@return the singleton instance of {@link PipeConfigNodePluginAgent}
iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/pipe/agent/PipeConfigNodeAgent.java