Speak TLS inside the simulation

[dhruvl]

TLS now runs inside the simulation, on every route a program can ask for it: create_connection(ssl=...), create_server(ssl=...), and start_tls on an established connection. The handshake is real — the standard library's SSLProtocol drives an ssl.SSLObject over a pair of memory BIOs, the same machinery uvloop reuses — with real certificate verification against whatever context the caller provides. No descriptor and no real socket anywhere: each flight OpenSSL produces leaves as one simulated packet paying the link's seeded latency, so a TLS connect costs the two round trips it costs in production, and ssl_handshake_timeout / ssl_shutdown_timeout are ordinary loop timers firing in virtual time. A handshake stalled by a partition burns sixty virtual seconds and milliseconds of wall clock.

What the transport had to learn: buffered-protocol delivery (SSLProtocol is a BufferedProtocol), protocol adoption in one place so start_tls can swap protocols mid-stream, and _force_close. All composed with the flow-control machinery — credits stay where the protocol takes the bytes, and _force_close routes through the same teardown that zeroes the write buffer.

Determinism, measured rather than promised: TLS bytes are random every run, but the trace hashes only the number and order of packets and callbacks, and SSLProtocol emits exactly one write per flight — so an EC leaf and an RSA leaf record the same hash, pinned by a test that re-mints the certificate between runs. What does move the hash is flight structure: the OpenSSL build and context settings like num_tickets. For TLS workloads the promise therefore gains one clause — same OpenSSL build, same TLS configuration — and only for TLS workloads: both reference workloads are held to pre-change digests across seeds, proving a run that never asks for TLS records exactly what it recorded before.

The compatibility table gains three measured rows, regenerated from the probes: aiohttp ClientSession over https:// (its sock_connect + create_connection(ssl=, sock=) path answered end to end), httpx over https:// (its own in-memory TLS, now with a simulated peer that speaks it), and websockets over wss:// (the one row exercising server-side TLS and client-side in one run). trustme mints throwaway in-memory CAs for tests and probes — dev and probes dependency groups only, nothing at runtime, no key material in the tree.

547 tests, the slow replay-stability suite (including TLS runs replayed across processes and hash seeds), and strict mypy are green; the per-step benchmark is unmoved (4.51 µs against the published ~4.4 µs).