Gets the counters of the document's render caches as they are now: decoded content, decoded images and masks, glyph outlines and display lists, each with its budget, the bytes and entries it holds, the most bytes it has held, and its hits, misses and evictions.
public PdfDocumentCacheStatistics CacheStatistics { get; }
Spec #33 viewer capability 13 and story 8. Each cache holds what rendering derives from the document, up to the budget set with WithContentCacheBudget(Int64), WithImageCacheBudget(Int64), WithGlyphCacheBudget(Int64) and WithDisplayListCacheBudget(Int64), dropping the least recently used entries to stay within it; a budget of zero turns that cache off without changing any output.
The caches are safe for any number of concurrent renders while nobody changes the document (the thread-safety contract on PdfDocument). An entry derived from many objects (an image with its masks and colour space, a display list) is current only while no COS object has changed through the public API since it was made, so after any edit, of this document or another, it is rebuilt at its next use; decoded content follows its own stream's changes only, and a glyph outline belongs to a parsed program that never changes.