Opens a document from a stream asynchronously (a browser file or a network stream): a stream that cannot seek is read into memory without blocking.
public static Task<DocumentSession> OpenAsync(Stream stream, ViewerOptions? options, CancellationToken cancellationToken)
The stream, which the caller keeps open for the session's lifetime when it can seek.
The session's options, or null for defaults.
Stops the read.
ISO 32000-2 §7.5.