tial</h4>
<pre><code><a href="Authentication.html#Struct_Credential">Credential</a></code> createCredential(<code>string</code> xiaomiAppId,
                            <code><a href="Authentication.html#Enum_AppUserAuthProvider">AppUserAuthProvider</a></code> appUserAuthProvider,
                            <code>string</code> authToken)
    throws <code><a href="Errors.html#Struct_ServiceException">Errors.ServiceException</a></code>
</pre>通过第三方认证系统换发Storage Access Token，采用App S