code: function onProcCall(method, path, args) {
      // log('Call:'+JSON.stringify(arguments));
      switch (method) {
      case 'GET': return onProcCallGet(path, args);
      case 'DELETE': return onProcCallDelete(path, args);
      }
      return {error: `The specified method ${method} is not implemented in this plugin.`};
  }
docs: onCall handler of plugin
  @param {string} method Caller method, accept GET only.
  @param {string} path Plugin URL path
  @param {object} args parameters of this call
  @return {object} Returns a Promise object or object containing the result