Does it support adding extra headers ?

I am wondering if there is or will it be add support to add custom or extra headers, ie is s3cmd we do:

s3cmd -v put --add-header=Content-Encoding:gzip --guess-mime-type . . . .

No files or tests are named. Start by locating the Python CLI entry point for the put operation and tracing how its options reach the S3 upload request; done means users can provide custom headers such as Content-Encoding, with behavior comparable to s3cmd's --add-header.

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