public TodoContext(DbContextOptions <TodoContext> options)
: base(options)
{
// System.Console.WriteLine("------------> DbContext");
Console.WriteLine($"DbContextOptions<TodoContext> options==>{options.GetHashCode()} {options.GetType().FullName}");
Console.WriteLine($"TodoContext:{++Amount}");
Console.WriteLine();
double d = System.Math.PI;
double d1 = d.Round(4);
}