public void Dispose_MustNotThrowAnExceptionIfTheMethodIsCalledMultipleTimes()
        {
            IDisposable instance = new NullDisposable();

            instance.Dispose();
            instance.Dispose();
        }
        public void DisposingHasNoSideEffects()
        {
            IDisposable instance = new NullDisposable();
            int         hashCode = instance.GetHashCode();

            instance.Dispose();
            Assert.Equal(hashCode, instance.GetHashCode());
        }