public void IsXml_DetectsXml(string input, bool expected)
        {
            // Arrange
            HttpContent content = new StringContent(string.Empty);
            content.Headers.ContentType = MediaTypeHeaderValue.Parse(input);

            // Act
            bool actual = content.IsXml();

            // Assert
            Assert.Equal(expected, actual);
        }
        public void IsXml_HandlesNullContentType()
        {
            // Arrange
            HttpContent content = new StringContent(string.Empty);
            content.Headers.ContentType = null;

            // Act
            bool actual = content.IsXml();

            // Assert
            Assert.False(actual);
        }