toJson method
Implementation
Map<String, dynamic> toJson() => {
'access_token': accessToken,
'token_type': tokenType,
if (expiresIn != null) 'expires_in': expiresIn,
if (refreshToken != null) 'refresh_token': refreshToken,
if (scopes != null) 'scope': scopes!.join(' '),
'issued_at': issuedAt.millisecondsSinceEpoch,
};