appsettings.json 

"JwtConfigOptions": {
  "Issuer": "xxx",
  "Audience": "xxx",
  "SecurityKey": "xxxxxxxx5oxxxx5xxxxxszkxxxxdlxxxbxxx"
}

builder.Configuration
       .AddEtcd("http://127.0.0.1:2379", new EtcdAuth("root", "123456"), "app1/production.json")
       .Build();

or

builder.Configuration
       .AddEtcd(options =>
       {
           options.ServiceUrl = "http://127.0.0.1:2379";
           options.Auth = new EtcdAuth("root", "123456");
           options.Keys.Add("app1/production.json");
       })
       .Build();

    private readonly IConfiguration _configuration;
    public MyConfiguration(IConfiguration configuration)
    {
        _configuration = configuration;
    }

    public JwtConfigOptions JwtConfig => _configuration.GetSection(nameof(JwtConfigOptions)).Get<JwtConfigOptions>();