Determines the index of a specific item in the IList<(Of <(<'T>)>)>.


- item (Id)
- The object to locate in the IList<(Of <(<'T>)>)>.

The index of item if found in the list; otherwise, -1.

- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)