v1.6.1

Proper iOS support, and minor bugfixes. No public interfaces were changed.

Bug fixes

• Fix crash when passing NULL to SetConfigValue for connection user data (#443)
• Listen sockets now reply to stray data packets from an unknown address
  with a "no connection" message, so a peer with a long timeout stops
  retrying promptly instead of sending keepalives until it times out
• Fix k_nSteamNetworkingSend_UnreliableNoDelay docs to describe actual behavior (#399)
• bcrypt crypto backend: fix memory leaks and buffer-size checks
• Fix race condition in Plat_IsInDebugSession (#430)

P2P / ICE

• The default ICE implementation now falls back to the native client if
  WebRTC is not compiled in or its DLLs fail to load
• Fix STUN/TURN failover stalling when several server entries resolve to
  the same address (#437)
• Multi-homed hosts: prefer same-subnet candidate pairs, and classify a
  route as local if the peer is on any of our subnets
• Don't queue the same candidate pair for a connectivity check twice
• Fix a race when handling P2P signals during async authentication
• Hardening of STUN attribute length checks

Platform support

• iOS, tvOS, and visionOS: CMake support, xcframework build scripts, and a
  BUILD_FRAMEWORK option. See BUILDING.md
• Android: recognized in CMake, link liblog, fix bionic INADDR_* constants
• Fix TSAN warnings (#429)
• Fix mingw-w64 build (CMSG_LEN)
• Fix compile error with some versions of clang
• Fix incorrect argument size in Windows x64 thread-naming code
• BUILDING.md: corrected CMake and C++ standard requirements, rewrote the
  macOS section, documented iOS builds

Tests / CI

• Fix connection state transition bug in example_chat (#269)
• Added iOS CI, a second macOS job building dependencies via Homebrew,
  manual workflow triggers, and scheduled soak tests
• Fixed flaky P2P test harness startup on Windows