Only one append path exists now: append(from:count:), which is what the
IO proc callback uses. The Data-based overload had no callers in source
and added a dead code path to maintain.
Also resolves CoreAudio.AudioBuffer name collision in tests via typealias.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Replace Swift Array<UInt8> ring buffer with UnsafeMutableRawPointer to
eliminate COW ref-count checks on every write/read
- Add append(from:count:) to copy directly from Core Audio buffer pointer
into the ring buffer, removing the per-callback Data heap allocation
- Pre-allocate AVAudioPCMBuffer pair in AudioFormatConverter and reuse
across transform() calls (lazy init, capacity-checked)
- Fix float-to-int truncation in output frame count calculation (ceil)
- Add comprehensive AudioBuffer test suite (12 tests) including proper
wrap-around coverage for both append and read paths
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Nick Payne