Get ignored properties in Entity Framework

I work on a framework with EF. I want to get all ignored properties of an entity to build some special queries. How can I do it?

public class Customer
{
    public int Id { get; set; }
    public DateTime BirthDate { get; set; }
    public int Age { get; set; }
}

public class CustomerContext : DbContext
{
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Customer>().Ignore(customer => customer.Age);
        base.OnModelCreating(modelBuilder);
    }

    public DbSet<Customer> Customers { get; set; }
}

public static class DbContextExtensions
{
    public static List<string> GetIgnoredProperties(this DbContext context, string entityTypeName)
    {
         // ???
    }
}