- Fixed incorrect init_connections() call in test_etcp_simple_traffic.c (was calling server_instance instead of client_instance)
- Fixed double free in timeout_heap_pop() when handling deleted elements
- Enhanced NULL pointer safety in uasync_print_resources() by removing complex heap manipulation
- Added debug logging to timeout_heap_pop() for better error tracking
Test results: test_etcp_simple_traffic now passes without double free errors
- Add utun VPN daemon with config parsing, control socket, routing, and TUN interface
- Refactor net_emulator/u_async to support multiple independent instances
- Replace linked-list timeout management with heap-based implementation
- Fix timeout processing bug (process timeouts after select)
- Add comprehensive random timeout and instance isolation tests
- Update Makefile to build utun and new test targets