Show a simple progress bar in the terminal window with basic options.
A sample example is given in the example directory. With 2 simple steps and an optional step a simple progressbar can be shown.
Create a simple Bar object
b := pbar.NewBar("sample.tar.xz")
Optionally setup the display variables which alters the speed display
b.SetSpeedInfo(300, "MB/s")
Update the progress
b.Update(34)