In v1.x the detect functions no longer return the MIME type and extension as strings. Instead they return a MIME struct. To get the string value of the MIME and the extension, call the String() and the Extension() methods.
In order to play better with the stdlib mime package, v1.x file extensions include the leading dot, as in ".html".
In v1.x the text/plain MIME type is text/plain; charset=utf-8.