IQueryable

    // Summary:
    //     Provides functionality to evaluate queries against a specific data source
    //     wherein the type of the data is known.
    //
    // Type parameters:
    //   T:
    //     The type of the data in the data source.This type parameter is covariant.
    //     That is, you can use either the type you specified or any type that is more
    //     derived. For more information about covariance and contravariance, see Covariance
    //     and Contravariance in Generics.
    public interface IQueryable : IEnumerable, IQueryable, IEnumerable
    {
    }