Content-Disposition header overwrite fails

[spidzio]

I am trying to overwrite the Content-Disposition header.

For the third party API, I need a very specific filename that includes /.
I noticed the Content-Disposition header is not entirely overwritten. It still adds the default name and filename.

require 'faraday'
require 'faraday/multipart'

connection = Faraday.new(url: 'http://localhost:3000') do |connection_builder|
  connection_builder.request :multipart
  connection_builder.response :logger, nil, { headers: true, bodies: true }
end

payload = { file: Faraday::Multipart::FilePart.new('test.txt', 'text/plain', nil, 'Content-Disposition' => 'form-data; name="file"; filename="foo/bar"') }

connection.post('path', payload)

It creates

Content-Disposition: form-data; name="file"; filename="foo/bar"; name="file"; filename="test.txt"

instead of

Content-Disposition: form-data; name="file"; filename="foo/bar"

I was also trying to give the file name as a parameter to the FilePart.new.

require 'faraday'
require 'faraday/multipart'

connection = Faraday.new(url: 'http://localhost:3000') do |connection_builder|
  connection_builder.request :multipart
  connection_builder.response :logger, nil, { headers: true, bodies: true }
end

payload = { file: Faraday::Multipart::FilePart.new('test.txt', 'text/plain', 'foo/bar') }

connection.post('path', payload)

It creates

Content-Disposition: form-data; name="file"; filename="bar"

while I need

Content-Disposition: form-data; name="file"; filename="foo/bar"