Presigned.Upload_parttype options = {expires_in : Ptime.Span.t option;URL lifetime. AWS S3 accepts at most seven days for SigV4 query authentication.
*)checksum : Object.Checksum.value option;Optional checksum header to sign for the part body.
*)customer_key : Encryption.Customer_key.t option;Optional SSE-C customer key headers to sign for the part upload.
*)expected_bucket_owner : Account_id.t option;x-amz-expected-bucket-owner header to sign.
extra_signed_headers : (string * string) list;Additional headers to include in the signature.
*)}Presigned UploadPart options.
val default_options : optionsDefault presigned UploadPart options.