Article 29 research notes, checked 2026-09-24.

Primary sources:
- Python 3.12 socket documentation, Python Software Foundation:
  https://docs.python.org/3.12/library/socket.html
  Checked blocking/non-blocking/timeout modes, recv empty-byte EOF, partial send,
  sendall semantics, and accepted-socket mode portability.
- Python 3.12 selectors documentation, Python Software Foundation:
  https://docs.python.org/3.12/library/selectors.html
  Checked DefaultSelector, readiness masks, registration and non-blocking examples.
- epoll(7), Linux man-pages project, rendered at man7.org, accessed 2026-09-24:
  https://man7.org/linux/man-pages/man7/epoll.7.html
  Checked interest/ready lists, level/edge triggering and the EAGAIN drain rule.
- RFC 9293, Transmission Control Protocol, IETF, August 2022:
  https://www.rfc-editor.org/rfc/rfc9293.html
  Checked half-close and user-timeout transport boundaries.

Environment:
- Python 3.12.3.
- Linux 5.10.134-013.16.kangaroo.al8.x86_64.
- selectors.DefaultSelector resolves at runtime and is recorded by lab.py.

Experiment boundary:
- Self-owned 127.0.0.1 listeners and synthetic payloads only.
- No benchmark, public service, kernel tuning, production traffic or resource-limit test.
- Thread count and selector-loop count describe this program structure, not capacity.