Worked on the apache/opendal repository to enhance SFTP backend reliability by implementing atomic write_with_if_not_exists semantics. Developed a feature in Rust that allows files to be written only if they do not already exist, using a post-operation check to ensure atomicity and prevent race conditions. Improved error handling by returning a specific ConditionNotMatch error when a file exists, rather than a generic failure, which aids in clearer diagnostics and aligns behavior with OpenSSH standards. Focused on backend development and robust error handling, these changes laid the foundation for safer cross-environment file operations and reduced support issues related to SFTP.