Tells the component not to prepare TSP request but pass just a hash to the event.
When HashOnlyNeeded is False, the component creates a TSP request and passes it to OnTimestampNeeded event.
When HashOnlyNeeded is True, the component passes the hash to be timestamped to OnTimestampNeeded event.
The hash can be needed when you use a third-party library to send the timestamping request and that library accepts just hashes.
Note, that if you set HashOnlyNeeded to True, you need to set HashAlgorithm property to the algorithm used to create a hash: the value is checked when the response is validated.