private static void CheckInvalidGetRangeLength(string input, int startIndex)
        {
            object result = null;

            Assert.Equal(0, RangeHeaderValue.GetRangeLength(input, startIndex, out result));
            Assert.Null(result);
        }
        private static void CallGetRangeLength(string input, int startIndex, int expectedLength,
                                               out RangeHeaderValue result)
        {
            object temp = null;

            Assert.Equal(expectedLength, RangeHeaderValue.GetRangeLength(input, startIndex, out temp));
            result = temp as RangeHeaderValue;
        }