This function should be called once you have added the text/html/images/attachments. It builds the message and returns it. It does not send it. To send what this function returns (in conjunction with the headers() -function) you would need to use the Mail::send()-function
array $param - An associative array of parameters. These parameters affect the way the message is built.
$param["text_encoding"] - Type of encoding to use for the plain text part of the email. Default is "7bit".
$param["html_encoding"] - Type of encoding for the HTML part of the email. Default is "quoted-printable".
$param["7bit_wrap"] - Number of characters after which text is wrapped. SMTP stipulates maximum line length of 1000 characters including CRLF. Default is 998 (CRLF is appended to make up to 1000).
$param["head_charset"] - The character set to use for the headers. Default is "iso-8859-1".
$param["text_charset"] - The character set to use for the plain text part of the email. Default is "iso-8859-1".
$param["html_charset"] - The character set to use for the HTML part of the email. Default is "iso-8859-1".