Useless Headers in body of REST POST while adding attachment

I am trying to post some attachments through a REST request. I have a dynamic list of files and I am sending files one at a time by attaching them to the request.
I am highlighting the portion I do not want in the request body. The file content is below the glowing portion. I am not able to paste all file content here. Why do we have the glowing part of the request? How do I get rid of it? I am adding my own headers as necessary.

Here is what I see in the Raw Request.

POST http://URLIamTryingTopostTo HTTP/1.1
Accept-Encoding: gzip,deflate
MIME-Version: 1.0
Cookie: WebSessionId=29572FC43B96EB9299DFFA6F8435388560C55B78AA506B41185226997D1C3E73
Content-type: application/octet-stream
Content-Disposition: attachment; filename="Thumbs.db"
Content-Length: 34049
Host: transfer.int.discoverysphere.ci.thomsonreuters.com
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.1.1 (java 1.5)


[glow]------=_Part_290_2042867758.1409938087944
Content-Type: application/octet-stream; name=Thumbs.db
Content-Transfer-Encoding: binary
Content-Disposition: form-data; name="Thumbs.db"; filename="Thumbs.db"[/glow]


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