Use Case

As a... developer
I want... to refactor the abstract cursor class: node-mongodb-native/src/cursor/abstract_cursor.ts
So that...

• It uses an enum instead of multiple flags like closed, killed, isDead, and better documents that usage
• Instead of `this[kId] === Long.ZERO` checks, it relies everywhere on `this[kId]?.isZero()` 

User Impact

None

Dependencies

None

Unknowns

None

Acceptance Criteria

Implementation Requirements

• Migrate closed, killed, isDead flags to enum
  • Document what happens when those values are being set
• Replace or occurrences of `this[kId] === Long.ZERO` with the `this[kId]?.isZero()` check

Documentation Requirements

None

Follow Up Requirements

None