Returns the indentation level for a given row.
Original signature is '- (NSInteger)levelForRow:(NSInteger)row'
Available in Mac OS X v10.0 and later.


- row (NSInteger)
- The index of a row in the receiver.

The indentation level for row. For an invalid row, returns –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)