Mail Index API
==============

'lib-index/mail-index.h' contains the functions to access the index files.
'mail-cache.h' contains the functions to access the cache file.

The purpose of the main structures are:

 * 'struct mail_index': Global state of the index.
 * 'struct mail_index_view': You can have multiple views to the index. The
   views see new messages come and expunged messages go only when it's being
   explicitly synchronized. With mmaped indexes you can't really trust the
   record data (flags,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      