Provides a decorator container that is able to store records
(of type
{@link xxl.core.io.Block}
) which are of different size. The size of each
record has to be below a maximum size which is again below the
pageSize.
A RecordManager can be used on top of each container. Usually,
it is used on top of a
{@link xxl.core.collections.containers.io.BlockFileContainer}
or a
{@link xxl.core.collections.containers.io.MultiBlockContainer}
.