close

Releases any underlying resources without producing output. Called by the renderer when rendering fails partway through (so finish is never reached) to avoid leaking native / file handles. Must be idempotent and safe to call after finish. The default is a no-op — backends whose resources are already freed by finish (or that hold none, like the Android PdfDocument / iOS CGContext backends) need not override it; the JVM PdfBox backend overrides it to close its PDDocument.