{
  "kit_reader": "=Email::MIME::Kit::ConstKit",
  "header": [
    { "Subject": "Hello"                       },
    { "From"   : "Test Sender <test@test.com>" }
  ],
  "alternatives": [
    {
      "type": "text/plain",
      "path": "first/text/alternative.txt"
    },
    {
      "type": "text/plain",
      "path": "second/text/alternative.txt"
    }
  ]
}