[ NoAccessorMethod ]
public int pulse { get; set; }
Setting this to a non-negative value causes the cell renderer to enter "activity mode", where a block bounces back and forth to indicate that some progress is made, without specifying exactly how much.
Each increment of the property causes the block to move by a little bit.
To indicate that the activity has not started yet, set the property to zero. To indicate completion, set the property to g_maxint.