Content-Type: multipart/mixed; boundary="1234567890123456789012345678901234567890123456789012345678901234567890123456789012"

--1234567890123456789012345678901234567890123456789012345678901234567890123456789012
Content-Type: multipart/mixed; boundary="123456789012345678901234567890123456789012345678901234567890123456789012345678901"

--123456789012345678901234567890123456789012345678901234567890123456789012345678901
Content-Type: multipart/mixed; boundary="12345678901234567890123456789012345678901234567890123456789012345678901234567890"

--12345678901234567890123456789012345678901234567890123456789012345678901234567890
Content-Type: text/plain

1
--1234567890123456789012345678901234567890123456789012345678901234567890123456789012
Content-Type: text/plain

22
--123456789012345678901234567890123456789012345678901234567890123456789012345678901
Content-Type: text/plain

333
--12345678901234567890123456789012345678901234567890123456789012345678901234567890
Content-Type: text/plain

4444

---- EXPECTED STRUCTURE ----
{
  "headers_rfc": {
    "content_type": {
      "ContentType": {
        "c_type": "multipart",
        "c_subtype": "mixed",
        "attributes": {
          "boundary": "1234567890123456789012345678901234567890123456789012345678901234567890123456789012"
        }
      }
    }
  },
  "headers_offsets": [
    {
      "name": {
        "Rfc": "content_type"
      },
      "start": 13,
      "end": 125
    }
  ],
  "html_body": [
    2
  ],
  "text_body": [
    2
  ],
  "attachments": [
    3
  ],
  "parts": [
    {
      "Multipart": {
        "content_type": {
          "ContentType": {
            "c_type": "multipart",
            "c_subtype": "mixed",
            "attributes": {
              "boundary": "123456789012345678901234567890123456789012345678901234567890123456789012345678901"
            }
          }
        }
      }
    },
    {
      "Multipart": {
        "content_type": {
          "ContentType": {
            "c_type": "multipart",
            "c_subtype": "mixed",
            "attributes": {
              "boundary": "12345678901234567890123456789012345678901234567890123456789012345678901234567890"
            }
          }
        }
      }
    },
    {
      "Text": {
        "headers": {
          "content_type": {
            "ContentType": {
              "c_type": "text",
              "c_subtype": "plain"
            }
          }
        },
        "body": "1\n--1234567890123456789012345678901234567890123456789012345678901234567890123456789012\nContent-Type: text/plain\n\n22\n--123456789012345678901234567890123456789012345678901234567890123456789012345678901\nContent-Type: text/plain\n\n333"
      }
    },
    {
      "Text": {
        "headers": {
          "content_type": {
            "ContentType": {
              "c_type": "text",
              "c_subtype": "plain"
            }
          }
        },
        "body": "4444\n"
      }
    }
  ],
  "structure": {
    "MultiPart": [
      1,
      [
        {
          "Part": 2
        },
        {
          "Part": 3
        }
      ]
    ]
  },
  "offset_header": 0,
  "offset_body": 126,
  "offset_end": 997
}