Fail
     31 Content-Type: text/plain; charset=us-ascii; format=flowed
     17 Content-Type: text/plain; charset=iso-8859-1
     11 Content-Type: text/plain; charset=us-ascii
      2 Content-Type: text/plain; charset=utf-8
      2 Content-Type: Text/Plain;
      1 Content-Type: multipart/mixed; 

Pass
      9 Content-Type: text/plain; charset=us-ascii; format=flowed
      6 Content-Type: text/plain; charset=UTF-8; format=flowed
      5 Content-Type: text/plain; charset=ISO-8859-1
      5 Content-Type: text/plain;charset=iso-8859-1
      5 Content-Type: Text/Plain;
      4 Content-type: text/plain; charset=ISO-8859-1; format=flowed
      4 Content-Type: multipart/alternative;
      3 Content-Type: text/plain; charset=us-ascii
      3 Content-Type: text/plain; charset="iso-8859-1"
      2 Content-Type: text/plain; charset=ISO-8859-1; format=flowed
      1 Content-Type: text/plain; charset="UTF-8"
      1 Content-Type: text/plain; charset="iso-8859-1"; format=flowed
      1 Content-Type: MULTIPART/MIXED;
      1 Content-Type: multipart/mixed; 
      1 Content-type: multipart/alternative;