Subject: RFC 8621 Section 4.1.4 test
Content-Type: multipart/mixed; boundary="1"

--1
Content-Type: text/plain
Content-Disposition: inline

A
--1  
Content-Type: multipart/mixed; boundary="2"

--2
Content-Type: multipart/alternative; boundary="3"

--3
Content-Type: multipart/mixed; boundary="4"

--4
Content-Type: text/plain
Content-Disposition: inline

B
--4  
Content-Type: image/jpeg
Content-Disposition: inline

C
--4  
Content-Type: text/plain
Content-Disposition: inline

D
--4--

--3 
Content-Type: multipart/related; boundary="5"

--5
Content-Type: text/html

<html>E</html>
--5  
Content-Type: image/jpeg

F
--5--  

--3-- 

--2   
Content-Type: image/jpeg
Content-Disposition: attachment

G
--2  
Content-Type: application/x-excel

H
--2  
Content-Type: message/rfc822

Subject: J

J
--2--

--1  
Content-Type: text/plain
Content-Disposition: inline

K
--1--

