Conditionally encodes a reference to objv and associates it with the string key only if objv has been unconditionally encoded with encodeObject:forKey:.
Original signature is '- (void)encodeConditionalObject:(id)objv forKey:(NSString *)key'
Available in Mac OS X v10.2 and later.


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