When i upload files to logstash by curl， A lot of things have been added to it

[chenzilong444]

	 http {
            host => "10.234.88.21"
            port => 8080
            additional_codecs => {"application/json"=>"json"}
			codec=> multiline{
				pattern => "^\["
				negate => true
				what => "previous"
				}

            threads => 10
            ssl => false
    }

when i curl "http://10.234.88.21:8080/" -F "img=@E:/temp/3.log"
[2018-02-08 11:39:40.720][27348:01*][F][Bigger_Example][Example.swift, logExample, 6666] hello world fatal
--------------------------d387f913c6b05399--
[2018-04-23 11:39:40.720][27348:01*][F][Bigger_Example][Example.swift, logExample, 6666] hello world Test
--------------------------ee3fc9056042a64d
Content-Disposition: form-data; name="img"; filename="2.log"
Content-Type: application/octet-stream
can i remove it？
and i find that I can see the last log on kibana only the next log uploads,