Reset the state of all messages marked for deletion.
Messages marked for deletion are not actually deleted until the session is cleanly disconnected (see IMailService.Disconnect(bool, CancellationToken)).
/// The has been disposed.
///
/// The is not connected.
///
/// The is not authenticated.
///
/// The operation was canceled via the cancellation token.
///
/// An I/O error occurred.
///
/// The command failed.
///
/// A protocol error occurred.
///
