Method in AsyncOptionsView
Called by a DialogueRunner when a line needs to be presented, and stores the line as the 'last seen line' so that it can be shown when options appear.
This view does not display lines directly, but instead stores lines so that when options are run, the last line that ran before the options appeared can be shown.
line
The line to present.
token
A that represents whether the dialogue view should hurry it its presentation of the line, or stop showing the current line.
A completed task.