public Task <GetTokenResult> ExecuteAsync(Uri tokenUri)
{
if (tokenUri == null)
{
throw new ArgumentNullException(nameof(tokenUri));
}
if (_requestBuilder.Certificate != null)
{
return(_postTokenOperation.ExecuteAsync(_requestBuilder.Content,
tokenUri,
_requestBuilder.AuthorizationHeaderValue,
_requestBuilder.Certificate));
}
return(_postTokenOperation.ExecuteAsync(_requestBuilder.Content,
tokenUri,
_requestBuilder.AuthorizationHeaderValue));
}