public virtual ISet<E> NewBigSet<E>()

creates a new BigSet.

Characteristics of BigSet:
- It is optimized by using a BTree of IDs of persistent objects.
- It can only hold persistent first class objects (no primitives, no strings, no objects that are not persistent)
- Objects are activated upon getting them from the BigSet.

BigSet is recommend whenever one object references a huge number of other objects and sorting is not required.