v0.4.0

A fast path between online devices. On-remote format unchanged (bothy_format = 1); the new
signaling files are optional and 0.3 readers ignore them. The Python and Flutter packages
have their own changelogs.

Added

• Direct channels between online devices (p2p feature, on by default but inactive until
  Config::p2p(P2pConfig)). While background sync runs, devices find each other through
  signaling files on the remote and open a WebRTC data channel
  (str0m; ICE with host and STUN candidates,
  stun.l.google.com by default, no TURN).
  • After uploading a segment, a device sends it to its peers (up to 64 KiB, otherwise an
    announcement), and they apply it at once. The remote stays the durable record: nothing
    is sent before it is uploaded, and without a channel sync works as before.
  • Measured p50 from a write to the other device: 1.1 to 1.7 s, against about 30 s by
    polling.
  • Database::p2p_status() (also in the blocking API) with P2pStatus::discovering and
    per-peer PeerState.
  • AutoSync::p2p_debounce (100 ms) is the write debounce while a channel is open.
    Background sync polls every 3 s while peers are being found.
  • A failed attempt is retried after 15 s, doubling up to 10 minutes. A device whose
    online file could not be written retries after 15 s.
• Signaling files: codec::keys::{KeyKind::Signal, SignalKind}
  (<db_id>/signaling/<device_id>/{online-<hlc>,offer-<peer>-<hlc>,answer-<peer>-<hlc>}.json)
  and codec::signal. They are sealed in encrypted databases, so SDPs and IP addresses never
  reach the remote in plain text. Conformance vectors: spec/vectors/signaling.json.
• CLI:
  • sync --watch --p2p, with --stun or --no-stun, prints peer state changes.
  • The hidden bench propagate (--peer for a second local database, or bench echo on
    another device) measures how long a write takes to reach another device.

Changed

• Drive: file ids are reserved 20 at a time, so most uploads need one request instead of two.
• codec::keys::KeyKind is #[non_exhaustive].
• AutoSync has a new field; struct literals need ..AutoSync::default().
• The p2p feature builds aws-lc-sys (C) for str0m's aws-lc-rs crypto backend.

Security

• No crypto-bigint 0.5 (RUSTSEC-2026-0387): P2P uses str0m's aws-lc-rs backend rather than
  its RustCrypto one.

Packages

• crates.io: bothy, bothy-cli, bothy-oauth
• PyPI: bothy 0.4.0, abi3 wheels for CPython 3.9+ on Linux (x86_64, aarch64, armv7), macOS (universal2) and Windows (x64); see bindings/python/CHANGELOG.md
• pub.dev: bothy 0.4.0; see bindings/flutter/CHANGELOG.md

Accepted live between the macOS CLI and the Flutter demo on an Android emulator, on one encrypted database (#71):

• 50 writes from the Mac reached the phone with p50 1.12 s, against about 30 s by polling.
• With the network cut, sync went on through Drive.
• The channel came back about 1.5 minutes after the network did.
• No plain-text addresses or SDPs reached the remote.