Comment 1 for bug 813573

Another use case for this is in retrieving a value that may be a primitive or a null. For instance, if we want to get a double, we can't just call key.decodeDouble() since it could be null. Instead, we have to call key.decode(), check if that's null, and then either unbox it or later call key.decodeDouble().

This is going to be somewhat important for the server, especially now that we support covering indexes.