Parses a file. This is the optimal way of parsing a mail file that you have on disk.
Path to the file holding the message. The file is opened and streamed through the parser.
The message contained in filename is supposed to end with a newline (CRLF); otherwise the last line of the message will not be parsed.
Returns a MIME resource representing the structure, or false on error.
It is recommended to call mailparse_msg_free on the result of this function, when it is no longer needed, to avoid memory leaks.