NotificationOptions.BacklogBytes

BacklogBytes bounds the notifications this stream holds while the caller is not reading, counting each notification's text and a small fixed overhead. Zero means 16 MiB. Once a notification would cross the bound, reads return the queued prefix and then ErrControlNotificationOverflow. A larger bound trades memory for headroom on a chatty pane; a smaller one makes a slow reader fail sooner. It may not be below 64 KiB.