问 创建apple JWT令牌

我试图从一个.core应用程序中获得application连接API。

我现在有

var key = <contents of p8 file>;
var credentials = new SigningCredentials(
    new SymmetricSecurityKey(Encoding.ASCII.GetBytes(key)),
    SecurityAlgorithms.EcdsaSha256
var header = new JwtHeader(credentials);
header.Add("kid", KeyID);   
var payload = new JwtPayload
    { "aud ", "appstoreconnect-v1"},
    { "exp", exp},