---input---
From: Some One <someone@example.com>
MIME-Version: 1.0
Content-Type: multipart/mixed;
        boundary="+Testboundary text"

This is a multipart message in MIME format.

--+Testboundary text
Content-Type: multipart/alternative;
        boundary="hello, boundary"

--hello, boundary
Content-Type: text/plain

this is the body text

--hello, boundary
Content-Type: text/html;
       charset="utf-8"
Content-Transfer-Encoding: quoted-printable

<font color=3D"#FF0000">This is the body text</font>

--hello, boundary--
--+Testboundary text
Content-Type: text/plain;
Content-Disposition: attachment;
        filename="test.txt"
Content-Transfer-Encoding: base64

dGhpcyBpcyB0aGUgYXR0YWNobWVudCB0ZXh0

--+Testboundary text--
Some additional content here.

---tokens---
'From: Some One <someone@example.com>\n' Comment

'MIME-Version: 1.0\n' Comment

'Content-Type:' Name.Tag
' '           Text.Whitespace
''            Text.Whitespace
'multipart'   Name.Label
'/'           Literal.String.Delimiter
'mixed'       Name.Label
';'           Text
'\n        '  Text.Whitespace
'boundary'    Name.Attribute
'='           Operator
'"+Testboundary text"' Literal.String
'\n'          Text.Whitespace

'\n'          Text.Whitespace

'This is a multipart message in MIME format.\n\n' Text

'--+Testboundary text\n' Literal.String.Delimiter

'Content-Type:' Name.Tag
' '           Text.Whitespace
''            Text.Whitespace
'multipart'   Name.Label
'/'           Literal.String.Delimiter
'alternative' Name.Label
';'           Text
'\n        '  Text.Whitespace
'boundary'    Name.Attribute
'='           Operator
'"hello, boundary"' Literal.String
'\n'          Text.Whitespace

'\n'          Text.Whitespace

''            Text
'--hello, boundary\n' Literal.String.Delimiter

'Content-Type:' Name.Tag
' '           Text.Whitespace
''            Text.Whitespace
'text'        Name.Label
'/'           Literal.String.Delimiter
'plain'       Name.Label
'\n'          Text.Whitespace

'\n'          Text.Whitespace

'this is the body text\n\n' Text

'--hello, boundary\n' Literal.String.Delimiter

'Content-Type:' Name.Tag
' '           Text.Whitespace
''            Text.Whitespace
'text'        Name.Label
'/'           Literal.String.Delimiter
'html'        Name.Label
';'           Text
'\n       '   Text.Whitespace
'charset'     Name.Attribute
'='           Operator
'"utf-8"'     Literal.String
'\n'          Text.Whitespace

'Content-Transfer-Encoding:' Name.Tag
' '           Text.Whitespace
'quoted-printable' Name.Constant
'\n'          Text.Whitespace

'\n'          Text.Whitespace

'<'           Punctuation
'font'        Name.Tag
' '           Text
'color'       Name.Attribute
'='           Operator
'3D"#FF0000"' Literal.String
'>'           Punctuation
'This is the body text' Text
'<'           Punctuation
'/'           Punctuation
'font'        Name.Tag
'>'           Punctuation
'\n\n'        Text

'--hello, boundary--\n' Literal.String.Delimiter

'--+Testboundary text\n' Literal.String.Delimiter

'Content-Type:' Name.Tag
' '           Text.Whitespace
''            Text.Whitespace
'text'        Name.Label
'/'           Literal.String.Delimiter
'plain'       Name.Label
';\n'         Text

'Content-Disposition: attachment;\n        filename="test.txt"\n' Comment

'Content-Transfer-Encoding:' Name.Tag
' '           Text.Whitespace
'base64'      Name.Constant
'\n'          Text.Whitespace

'\n'          Text.Whitespace

'dGhpcyBpcyB0aGUgYXR0YWNobWVudCB0ZXh0\n\n' Other

'--+Testboundary text--\n' Literal.String.Delimiter

'Some additional content here.\n' Text
