From: sender@example.com
To: recipient@example.com
Subject: Multipart Email Example
Content-Type: multipart/alternative; boundary="boundary-string"

--boundary-string
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline

Plain text email goes here!
This is the fallback if email client does not support HTML

--boundary-string
Content-Type: text/html; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline

<h1>This is the HTML Section!</h1>
<p>This is what displays in most modern email clients</p>

--boundary-string--

---- EXPECTED STRUCTURE ----
{
  "header": {
    "from": {
      "Address": {
        "address": "sender@example.com"
      }
    },
    "subject": "Multipart Email Example",
    "to": {
      "Address": {
        "address": "recipient@example.com"
      }
    },
    "content_type": {
      "c_type": "multipart",
      "c_subtype": "alternative",
      "attributes": {
        "boundary": "boundary-string"
      }
    }
  },
  "html_body": [
    {
      "header": {
        "content_disposition": {
          "c_type": "inline"
        },
        "content_transfer_encoding": "quoted-printable",
        "content_type": {
          "c_type": "text",
          "c_subtype": "html",
          "attributes": {
            "charset": "utf-8"
          }
        }
      },
      "contents": "<h1>This is the HTML Section!</h1>\n<p>This is what displays in most modern email clients</p>\n"
    }
  ],
  "text_body": [
    {
      "header": {
        "content_disposition": {
          "c_type": "inline"
        },
        "content_transfer_encoding": "quoted-printable",
        "content_type": {
          "c_type": "text",
          "c_subtype": "plain",
          "attributes": {
            "charset": "utf-8"
          }
        }
      },
      "contents": "Plain text email goes here!\nThis is the fallback if email client does not support HTML\n"
    }
  ]
}