Can the pretty cool TUI remain on my shell even after training finished?

[kingwingfly]

Feature description

I'd prefer the TUI remains on my shell after training finished.

Feature motivation

So that I can observe the scatter diagram better.

(Optional) Suggest a Solution

let learner = LearnerBuilder::new(artifact_dir)
        .metric_train_numeric(LossMetric::new())
        ...
        .manually_quit()    // <- allow this
        .build(
            ...
        );