public PersonaViewModel()
{
Personas = servicio.consultar();
GuardarCommand = new Command(async() => await Guadar(), () => !IsBusy);
ModificarCommand = new Command(async() => await Modificar(), () => !IsBusy);
EliminarCommand = new Command(async() => await Eliminar(), () => !IsBusy);
LimpiarCommand = new Command(Limpiar, () => !IsBusy);
}