**Use case**
Some program left garbage in terminal.

**Describe the solution you'd like**
Subset of what `reset` command does.
}
    void onExtremes(Block & block)
    
        initBlockOutputStream(block);
        block_out_stream->setExtremes(block);
    }
    void onProgress(const Progress & value)
    
        if (!progress.incrementPiecewiseAtomically(value))
        
            // Just a keep-alive update.
            return;
        }
        if (block_out_stream)
            block_out_stream->onProgress(value);
        writeProgress();
    }
    void clearProgress()
    
        if (written_progress_chars)
        
            written_progress_chars = 0;
            std::cerr << "\r" CLEAR_TO_END_OF_LINE;
        }
    }
    void writeProgress()
    
        if (!need_render_progress)
            return;
        /// Output all progress bar commands to stderr at once to avoid flicker.