code: public String summarize()
      {
          return String.format(SUMMARY_FORMAT,
                  action, clientId, subject, existent, usable,
                  sufficient, refreshable, expiresAt,
                  Utils.join(scopes, " "),
                  Utils.stringifyProperties(properties),
                  clientIdAlias, clientIdAliasUsed,
                  certificateThumbprint);
      }
docs: Get the summary of this instance.