Differrence between drawn & created functionalities of VLayout SmartGWT

[RAS]

Hello All,
I've found three functionalities in VLayout:

vLayout.isDrawn()
vLayout.isAttached()
vLayout.isCreated()

These functionalities are inherited from its super classes. Can anyone tell me the difference between the three? Or when the VLayout is said to be drawn, created, attached?

Thanks in advance.