ManagementApiClient missing FirstName LastName

The quick fix for that would be to use UserMetadata directly

var users = await client.Users.GetAllAsync();  
            var enumerable = users
                .Select(p => new
                {
                    FirstName = string.IsNullOrWhiteSpace(p.FirstName) ? p.UserMetadata?.given_name : p.FirstName,
                    LastName = string.IsNullOrWhiteSpace(p.LastName) ? p.UserMetadata?.family_name : p.LastName});

But I wish I could get the FirstName and the LastName directly from the API like:

 var client = new ManagementApiClient(tokenResponse.AccessToken, 
           new Uri(_auth0Options.Value.ApiIdentifier));      
var users = await client.Users.GetAllAsync(); 
var result= users.Select(p => new {p.FirstName, p.LastName })

As I already have a rule

function (user, context, callback) {  
  if (user.user_metadata.given_name) 
    user.given_name = user.user_metadata.given_name;
  
  if (user.user_metadata.family_name) 
    user.family_name = user.user_metadata.family_name;   
  callback(null, user, context);
}