POST http://localhost/
Content-Length: 219
Content-Type: multipart/form-data; boundary=xYzZY

--xYzZY
Content-Disposition: form-data; name="file_name"; filename="test.csv"
Content-Type: application/vnd.ms-excel

foo;bar;baz
1;2;3

--xYzZY
Content-Disposition: form-data; name="submit"

Submit
--xYzZY--