Adds the validation data of every signature to the document security store and writes the document to
stream, as AddValidationData(Stream, PdfSignatureValidationOptions?) does, fetching and writing asynchronously.
public Task AddValidationDataAsync(Stream stream, PdfSignatureValidationOptions? options = null, CancellationToken cancellationToken = default(CancellationToken))
Where to write, from its current position. It is not disposed.
The validation options; null for none.
Cancels the fetches and the writes.
ISO 32000-2 §12.8.4.3, §12.8.4.4; ETSI EN 319 142-1 (B-LT). A cancelled or failed validation leaves the document as it was.