setInfo
fun setInfo(title: String? = null, author: String? = null, subject: String? = null, keywords: String? = null, creator: String? = null, producer: String? = null): PdfReference
Set document metadata (/Info). Only non-null fields are changed; any existing /Info entries (standard or custom) are preserved. Updates the existing /Info object in place if the trailer references one, otherwise creates a new /Info object and points the trailer at it. Returns the reference to the (possibly newly created) /Info dictionary.