s3transfer

s3transfer is an Amazon S3 Transfer Manager for Python, maintained by Amazon Web Services. It provides managed multipart uploads and downloads, automatic retries, progress callbacks, bandwidth throttling, and optional AWS CRT-accelerated transfers. As of version 0.16.0 it defaults to CRC32 checksums and supports user-provided full-object checksums. The project is NOT yet generally available (GA); minor-version bumps may contain breaking interface changes, so production deployments must pin to a minor version. It is bundled as a dependency of boto3 and botocore and is typically consumed indirectly through those SDKs.