the doc was outdated behavior

Author: TingDaoK

awscrt/s3.py

@@ -186,16 +186,10 @@ class S3FileIoOptions:
     """
     Enable direct IO to bypass the OS cache. Helpful when the disk I/O outperforms the kernel cache.
 
-    - Currently only Linux supports direct I/O. On unsupported platforms, the request transparently
-      falls back to buffered I/O and a warning is logged.
-    - Supported for both upload (send_filepath) and download (recv_filepath).
-    - For upload, part_size MUST be page-aligned when direct_io is enabled (hard fail otherwise).
-      The client controls part_size and is responsible for ensuring alignment.
-    - For download, this is a best-effort optimization. The request transparently falls back to
-      buffered I/O (logging a warning) if any of the following preconditions are not met:
-      part_size is not page-aligned, recv_file_position is not page-aligned (WRITE_TO_POSITION),
-      existing file size is not page-aligned (CREATE_OR_APPEND), or the last part has an
-      unaligned length (only that part falls back).
+    - This is a BEST-EFFORT optimization. The request transparently falls back to
+      buffered I/O (logging a warning) on unsupported platforms or when alignment
+      preconditions are not met (part_size not page-aligned, last part has unaligned
+      length, etc).
     - Check NOTES for O_DIRECT for additional info https://man7.org/linux/man-pages/man2/openat.2.html
 
     In summary, O_DIRECT is a potentially powerful tool that should be used with caution.