Would like to have a command for priming index by a sequential read of the index data instead of a B-tree traverse.

Currently in order to prime an index of a collection, we have to do a special query to force mongo go thru the entire BTree for the index. This trick is extremely inefficient for a large index tree (over 10 millions entries). Would like to have a command (please make it available in C++ driver) to prime collection data – either index or data or both, by simply doing a sequential read of the data extents for the collection.