<message>
<header>
<field>
Content-Type: multipart/mixed; boundary="0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  "</field>
</header>
<multipart>
<preamble>
multipart
</preamble>
<body-part>
<header>
<field>
Content-Type: text/plain; charset=us-ascii</field>
<field>
Content-Transfer-Encoding: 7bit</field>
</header>
<body>
Text body
--0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=?  0123456789abcdefghijklmnopqrstuvwxyzABCDEFLMNOPRSTUVWXYZ'()+_,-./:=? 
The above line is similar to the boundary but miss a final space, so it
should be part of the body.
</body>
</body-part>
<epilogue>
epilogue</epilogue>
</multipart>
</message>