用户分配托管标识的Principal Type是什么？角色分配报错求助

在为存储账户添加角色分配时，使用用户分配托管身份，代码如下：

RoleAssignmentCreateOrUpdateContent roleData = new RoleAssignmentCreateOrUpdateContent(
   roleDefinitionId: new ResourceIdentifier(string.Concat("/subscriptions/", SubscriptionId, "/providers/Microsoft.Authorization/roleDefinitions/", roleId)),
   principalId: PrincipalId);

执行时遇到如下错误：

ERROR: {"error":{"code":"PrincipalNotFound","message":"Principal xxx does not exist in the directory xxx. Check that you have the correct principal ID. If you are creating this principal and then immediately assigning a role, this error might be related to a replication delay. In this case, set the role assignment principalType property to a value, such as ServicePrincipal, User, or Group.  See https://aka.ms/docs-principaltype"}}       

错误提示建议添加principalType属性，请问用户分配托管身份对应的principalType是User、Group还是ServicePrincipal？

用户分配托管身份对应的principalType是ServicePrincipal。

用户分配托管身份本质是Azure AD中的服务主体对象，指定该类型可以规避因目录复制延迟引发的PrincipalNotFound错误。

修改后的代码示例：

RoleAssignmentCreateOrUpdateContent roleData = new RoleAssignmentCreateOrUpdateContent(
   roleDefinitionId: new ResourceIdentifier(string.Concat("/subscriptions/", SubscriptionId, "/providers/Microsoft.Authorization/roleDefinitions/", roleId)),
   principalId: PrincipalId,
   principalType: PrincipalType.ServicePrincipal);

内容的提问来源于stack exchange，提问作者ranger