Tell the scanner if it should scan "^From " lines or not.
If the scanner is scanning from lines, two additional states CAMEL_MIME_PARSER_STATE_FROM and CAMEL_MIME_PARSER_STATE_FROM_END will be returned to the caller during parsing.
This may also be preceeded by an optional CAMEL_MIME_PARSER_STATE_PRE_FROM state which contains the scanned data found before the From line is encountered. See also scan_pre_from.
| this |
MIME parser object |
| scan_from |
true if the scanner should scan From lines. |