/// <summary>
 /// Lists the asynchronous.
 /// </summary>
 /// <param name="token">The cancellation token that can be used by other objects or threads to receive notice of cancellation.</param>
 /// <returns>Task&lt;IEnumerable&lt;EmployeeModel&gt;&gt;.</returns>
 public Task <IEnumerable <EmployeeModel> > ListAsync(CancellationToken token)
 {
     token.ThrowIfCancellationRequested();
     return(Task.Run(() => (IEnumerable <EmployeeModel>)_emp.EmployeeCollection()));
 }