A path to a file. If a URL is provided, it must use the file:
protocol.
The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8'
is used.
Optional
options: null | "ascii" | "utf8" | "utf-8" | "utf16le" | "utf-16le" | "ucs2" | "ucs-2" | "base64" | "base64url" | "latin1" | "binary" | "hex" | ObjectEncodingOptions
Asynchronous realpath(3) - return the canonicalized absolute pathname.