docs: function pingIndex(opts, cb) {
      assert.object(opts, 'opts');
      assert.string(opts.indexName, 'opts.indexName');
      assert.optionalBool(opts.insecure, 'opts.insecure');
      assert.optionalObject(opts.log, 'opts.log');
      assert.optionalString(opts.userAgent, 'opts.userAgent');
      assert.func(cb, 'cb');
  
      var index = common.parseIndex(opts.indexName);
      var client = restifyClients.createJsonClient({
          url: common.urlFromIndex(index),
          log: opts.log,
          userAgent: opts.userAgent || common.DEFAULT_USERAGENT,
          rejectUnauthorized: !opts.insecure,
          // Want to fail fast:
          retry: false,
          connectTimeout: 10000
      });
  
      client.get({
          path: '/v1/_ping'
      }, function _afterPing(err, req, res, obj) {
          client.close();
          if (err) {
              return cb(err);
          }
          return cb(null, obj, res);
      });
  }