case insensitive contains and equals in the least garbage-making way possible

StringExtensions.cs

public static class StringExtensions
{
    /// <summary>
    ///     Check if a string contains another case insensitively.
    /// </summary>
    /// <param name="text">string to search in</param>
    /// <param name="value">string to search for</param>
    /// <param name="stringComparison">comparison option enum</param>
    /// <returns></returns>
    public static bool CaseInsensitiveContains(this string text, string value,
        StringComparison stringComparison = StringComparison.CurrentCultureIgnoreCase) =>
        text.IndexOf(value, stringComparison) >= 0;

    
    /// <summary>
    /// Compares strings creating the least amount of garbage possible 
    /// </summary>
    /// <param name="firstString">first string to compare</param>
    /// <param name="secondString">second string to compare</param>
    /// <returns></returns>
    public static bool CaseInsensitiveEquals (string firstString, string secondString) => string.Equals(firstString,secondString,StringComparison.OrdinalIgnoreCase);
    
}