This is readonly property that specifies Index value of
the user in the collection of all users. Please note that
this value changes on the fly, and you shouldn't store
it locally and then use after some time. For instance, if
there are two user's, and first one disconnects before
second, then Index value from second will change from 1 to
0. If you stored value 1 locally, you will get an error
while attempting to access that user, or you will access
some other user.
If you need distinct number to make difference between
users, you should try to use Tag property.
Please note that, unlike native collections in VB,
indexes in wodPop3Server start at 0 and go up to Count-1.
Index Property
(Pop3User)
