Add ability to grab delimiters and whitespace during parsing and make it available for read (create JsonTextReader with grabDelimiters option).
Add ability to clone the reader. Cloning can be used to return to parsing position at time when clone was created given that source stream is in the same position/buffer as when clone was created.
Add ability to get the number of characters in internal reading buffer which were not yet been parsed.
Make CloseInput virtual (e.g. for decorators)