- load_files_multithreaded skips file_load_data when sendfile is active
- -f + -m works: sendfile bypasses loader, sender uses sendfile directly
- -f combined with -c or -s prints error and exits with rc=1
- Add Sendfile + Multithreading test case
- Add file_send_sendfile() using sendfile() syscall to send file
content directly from fd to socket, bypassing userspace memory
- Add use_sendfile field to Config struct (default false)
- Add -f / --sendfile flag parsing in client.c
- sendfile path in send_chunk() used when -f is set without -c or -s
- send_files_multithreaded() falls back to single-threaded when
sendfile is enabled (loader pipeline becomes unnecessary)
- Add Sendfile (-f) test case to test.py
- Replace env var control (FASTSYNC_SOURCE_DIR, FASTSYNC_DEST_DIR,
FASTSYNC_SAVE_TO_DISK) with explicit --source-dir, --dest-dir,
--save-to-disk CLI arguments
- Keep env vars as fallback for backward compatibility
- Fix test.py: split '-c 0' into separate args ['-c', '0']
- Fix test.py: throttled suite failed because systemd-run didn't
inherit env vars; now all settings are passed as CLI args
- Add env_name to exception/timeout result entries for correct display