To: Yourself <you@here.tld>
Subject: The subject is not the object
-This is the body of the message.
+This is the body of the message. Make the line longer than any header.
****
sudo exim -be -Mset $msg1
From: $h_from:
message_size=$message_size
message_id=$message_id
message_exim_id=$message_exim_id
+max_received_linelength=$max_received_linelength
+recipients=$recipients
+****
+exim -bs
+mail from:<userz@test.ex>
+rcpt to:<userx@test.x>
+rcpt to:<usery@test.ex>
+data
+From: Himself <himself@there.tld>
+To: Yourself <you@here.tld>
+Subject: The subject is not the object
+
+This is the body of the message. Make the line much longer than any header.
+.
+quit
+****
+sudo exim -be -Mset $msg2
+From: $h_from:
+Subject: $h_subject:
+message_body_size=$message_body_size
+message_size=$message_size
+message_id=$message_id
+message_exim_id=$message_exim_id
+max_received_linelength=$max_received_linelength
recipients=$recipients
****
write test-data
message_exim_id=$message_exim_id
message_linecount=$message_linecount
message_body_linecount=$body_linecount
+max_received_linelength=$max_received_linelength
headers -----------------
$message_headers