Function copy_dir_all 

pub fn copy_dir_all(src: &Path, dst: &Path) -> Result<()>

Recursively copies a directory whilst maintaining structure and attributes.

Performs a deep copy of a directory tree, preserving file attributes and handling nested directories. Uses parallel processing for improved performance.

Arguments

• src - Source directory path
• dst - Destination directory path

Returns

• Ok(()) - If the copy operation succeeds
• Err - If any part of the copy operation fails

Performance

Uses rayon for parallel processing of files, significantly improving performance for directories with many files.

Safety

• Verifies file safety before copying
• Maintains original file permissions
• Handles circular references