title: Retrofit for android @Multipart remove default headers
body: <p>Making a @Multipart request adds these default headers (Content-Transfer-Encoding, Content-Type) for each part, is there any way to remove them?</p>
  
  <pre><code>//REQUEST BODY
  --25d35373-d2c3-46a3-969f-f5a1fd5f781a 
  Content-Disposition: form-data; name="client_id"
  Content-Transfer-Encoding: binary &lt;-- remove this one
  Content-Type: application/json; charset=UTF-8 &lt;-- remove this one
  Content-Length: 34
  "40ccfee680a844780a41fbe23ea89934"
  //
  </code></pre>
  
  <p>NOTE: I do not have access to the server so there is no way I will be able to make the server accept these headers.</p>