mailcore -- IMAP

MCOIMAPSession *session = [[MCOIMAPSession alloc] init];
    [session setHostname:@"imap.gmail.com"];
    [session setPort:993];
    [session setUsername:@"[e-mail]"];
    [session setPassword:@"*******"];
    [session setConnectionType:MCOConnectionTypeTLS];
    
    MCOIMAPMessagesRequestKind requestKind = MCOIMAPMessagesRequestKindHeaders;
    NSString *folder = @"INBOX";
    MCOIndexSet *uids = [MCOIndexSet indexSetWithRange:MCORangeMake(1, UINT64_MAX)];
    
    MCOIMAPFetchMessagesOperation *fetchOperation = [session fetchMessagesByUIDOperationWithFolder:folder requestKind:requestKind uids:uids];
    
    [fetchOperation start:^(NSError * error, NSArray * fetchedMessages, MCOIndexSet * vanishedMessages) {
       
        
      
        if(error) {
            NSLog(@"Error downloading message headers:%@", error);
        }
        
     
        NSLog(@"The post man delivereth:%@", fetchedMessages);
    }];