Returns the positions that are common to all the given iterators Expects each given iterator to be sorted from the smallest to the biggest position.

Ends when both the record and error are nil at the same time a nil record with a non-nil error does not mean it reached the end When the end has been reached, the iterator is expected to return (nil, nil), even if called again.

Ends when both the position and error are nil at the same time a nil position with a non-nil error does not mean it reached the end When the end has been reached, the iterator is expected to return (nil, nil), even if called again.