AddQueryString method to add the given query string key value pair appropriately to the given URL string.

DetectFileContentType method to identify the static file content-type.

FirstNonEmpty method returns the first non-empty string from given var args otherwise empty string.

FuncEqual method to compare to function callback interface data.

IsGzipWorthForFile method to decide whether gzipping file content it worth to do by checking file extension.

IsValidTimeUnit method to check supported time unit suffixes.

MimeTypeByExtension method to get MIME info by file extension with corner case covered since mime.TypeByExtension behaves wired on windows for `.js` and `.css`, it better to have some basic measure.

OnlyMIME method to strip everything after `;` from the content type value.

SanitizeValue method to sanatizes type `string`, rest we can't do any.