Made set_header() public in Email library and updated documentation.
diff --git a/user_guide_src/source/libraries/email.rst b/user_guide_src/source/libraries/email.rst
index daf0009..f99eb91 100644
--- a/user_guide_src/source/libraries/email.rst
+++ b/user_guide_src/source/libraries/email.rst
@@ -182,6 +182,14 @@
accept HTML email. If you do not set your own message CodeIgniter will
extract the message from your HTML email and strip the tags.
+$this->email->set_header()
+-----------------------
+
+Appends additional headers to the e-mail::
+
+ $this->email->set_header('Header1', 'Value1');
+ $this->email->set_header('Header2', 'Value2');
+
$this->email->clear()
---------------------