问使用Google Apps API Explorer时，我应该将什么设置为PageToken值？

EN

/// <summary>
/// List all Members in a Domain Group.
/// <param name="service">DirectoryService object (Google Directory API)</param>
/// <returns>Collection of Member emails</returns>
/// </summary>
public IEnumerable<string> ListGroupMembers(DirectoryService service)
{
    // Set Group key (email address of the Group or id of the Group)
    var groupKey = "email-for-google-group@domain-name.com";

    // Define parameters of request (Group email)
    MembersResource.ListRequest request = service.Members.List(groupKey);

    // Sadly, this won't work
    request.MaxResults = int.MaxValue;

    // And the max page size of response is ONLY 200!

    // So you have to check for the next page token
    // and execute another request if there is one

    do
    {
        // Get Members response for this Group
        Members response = request.Execute();

        // Return the emails in this response page
        foreach (var member in response.MembersValue)
        {
            yield return member.Email;
        }

        // Get next page token
        request.PageToken = response.NextPageToken;

        // Continue loop if next page token is not null
    } while (!string.IsNullOrEmpty(request.PageToken));
}