private bool IsSpecialRequestHeaderField(RequestHeaderFields key)
 {
     return key == RequestHeaderFields.IfModifiedSince ||
            key == RequestHeaderFields.Range ||
            key == RequestHeaderFields.IfUnmodifiedSince;
 }
 /// <summary>
 /// Determines whether {CC2D43FA-BBC4-448A-9D0B-7B57ADF2655C}[is a special request header field] [the specified key].
 /// </summary>
 /// <param name="key">The key.</param>
 /// <returns>
 ///     <c>true</c> if [is special request header field] [the specified key]; otherwise, <c>false</c>.
 /// </returns>
 private bool IsSpecialRequestHeaderField(RequestHeaderFields key)
 {
     return(key == RequestHeaderFields.IfModifiedSince ||
            key == RequestHeaderFields.Range ||
            key == RequestHeaderFields.IfUnmodifiedSince);
 }