ToString method will return string expression that is
combined of header Name, semicolon and
header Value,
just as it appears in email body. For example, if header
Name is 'From' and header value is
'techsupport@weonlydo.com ' then ToString would
return line like this:
From: techsupport@weonlydo.com
Notice that between Name and Value is one semicolon and
one space character.