Net::HTTPGenericRequest#send_request_with_body_data

# File tmp/rubies/ruby-3.4.1/lib/net/http/generic_request.rb, line 286
def send_request_with_body_data(sock, ver, path, params)
  if /\Amultipart\/form-data\z/i !~ self.content_type
    self.content_type = 'application/x-www-form-urlencoded'
    return send_request_with_body(sock, ver, path, URI.encode_www_form(params))
  end

  opt = @form_option.dup
  require 'securerandom' unless defined?(SecureRandom)
  opt[:boundary] ||= SecureRandom.urlsafe_base64(40)
  self.set_content_type(self.content_type, boundary: opt[:boundary])
  if chunked?
    write_header sock, ver, path
    encode_multipart_form_data(sock, params, opt)
  else
    require 'tempfile'
    file = Tempfile.new('multipart')
    file.binmode
    encode_multipart_form_data(file, params, opt)
    file.rewind
    self.content_length = file.size
    write_header sock, ver, path
    IO.copy_stream(file, sock)
    file.close(true)
  end
end