async function listUsers(auth) {
  const service = google.admin({version: 'directory_v1', auth});
  const res = await service.users.list({
    customer: 'my_customer',
    maxResults: 10,
    orderBy: 'email',
  });

  const users = res.data.users;
  if (!users || users.length === 0) {
    console.log('No users found.');
    return;
  }

  console.log('Users:');
  users.forEach((user) => {
    console.log(`${user.primaryEmail} (${user.name.fullName})`);
  });
}
Lists the first 10 users in the domain.

@param {google.auth.OAuth2} auth An authorized OAuth2 client.