Search email functionality in MailCore 2 (iOS/Swift)

Question

I am implementing MailCore2 to fetch user's email in my app. I have successfully fetched the email of the user, code is as follows : -

- (void)loadAccountWithUsername:(NSString *)username
                       password:(NSString *)password
                       hostname:(NSString *)hostname
                    oauth2Token:(NSString *)oauth2Token
{
    self.imapSession = [[MCOIMAPSession alloc] init];
    self.imapSession.hostname = hostname;
    self.imapSession.port = 993;
    self.imapSession.username = username;
    self.imapSession.password = password;
    if (oauth2Token != nil) {
        self.imapSession.OAuth2Token = oauth2Token;
        self.imapSession.authType = MCOAuthTypeXOAuth2;
    }
    self.imapSession.connectionType = MCOConnectionTypeTLS;
    MasterViewController * __weak weakSelf = self;
    self.imapSession.connectionLogger = ^(void * connectionID, MCOConnectionLogType type, NSData * data) {
        @synchronized(weakSelf) {
            if (type != MCOConnectionLogTypeSentPrivate) {
//                NSLog(@"event logged:%p %i withData: %@", connectionID, type, [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
            }
        }
    };

    // Reset the inbox
    self.messages = nil;
    self.totalNumberOfInboxMessages = -1;
    self.isLoading = NO;
    self.messagePreviews = [NSMutableDictionary dictionary];
    [self.tableView reloadData];

    NSLog(@"checking account");
    self.imapCheckOp = [self.imapSession checkAccountOperation];
    [self.imapCheckOp start:^(NSError *error) {
        MasterViewController *strongSelf = weakSelf;
        NSLog(@"finished checking account.");
        if (error == nil) {
            [strongSelf loadLastNMessages:NUMBER_OF_MESSAGES_TO_LOAD];
        } else {
            NSLog(@"error loading account: %@", error);
        }

        strongSelf.imapCheckOp = nil;
    }];
}

- (void)loadLastNMessages:(NSUInteger)nMessages
{
    self.isLoading = YES;

    MCOIMAPMessagesRequestKind requestKind = (MCOIMAPMessagesRequestKind)
    (MCOIMAPMessagesRequestKindHeaders | MCOIMAPMessagesRequestKindStructure |
     MCOIMAPMessagesRequestKindInternalDate | MCOIMAPMessagesRequestKindHeaderSubject |
     MCOIMAPMessagesRequestKindFlags);

    NSString *inboxFolder = @"INBOX";
    MCOIMAPFolderInfoOperation *inboxFolderInfo = [self.imapSession folderInfoOperation:inboxFolder];

    [inboxFolderInfo start:^(NSError *error, MCOIMAPFolderInfo *info)
    {
        BOOL totalNumberOfMessagesDidChange =
        self.totalNumberOfInboxMessages != [info messageCount];

        self.totalNumberOfInboxMessages = [info messageCount];

        NSUInteger numberOfMessagesToLoad =
        MIN(self.totalNumberOfInboxMessages, nMessages);

        if (numberOfMessagesToLoad == 0)
        {
            self.isLoading = NO;
            return;
        }

        MCORange fetchRange;

        // If total number of messages did not change since last fetch,
        // assume nothing was deleted since our last fetch and just
        // fetch what we don't have
        if (!totalNumberOfMessagesDidChange && self.messages.count)
        {
            numberOfMessagesToLoad -= self.messages.count;

            fetchRange =
            MCORangeMake(self.totalNumberOfInboxMessages -
                         self.messages.count -
                         (numberOfMessagesToLoad - 1),
                         (numberOfMessagesToLoad - 1));
        }

        // Else just fetch the last N messages
        else
        {
            fetchRange =
            MCORangeMake(self.totalNumberOfInboxMessages -
                         (numberOfMessagesToLoad - 1),
                         (numberOfMessagesToLoad - 1));
        }

        self.imapMessagesFetchOp =
        [self.imapSession fetchMessagesByNumberOperationWithFolder:inboxFolder
                                                       requestKind:requestKind
                                                           numbers:
         [MCOIndexSet indexSetWithRange:fetchRange]];

        [self.imapMessagesFetchOp setProgress:^(unsigned int progress) {
            NSLog(@"Progress: %u of %u", progress, numberOfMessagesToLoad);
        }];

        __weak MasterViewController *weakSelf = self;
        [self.imapMessagesFetchOp start:
         ^(NSError *error, NSArray *messages, MCOIndexSet *vanishedMessages)
        {
            MasterViewController *strongSelf = weakSelf;
            NSLog(@"fetched all messages.");

            self.isLoading = NO;

            NSSortDescriptor *sort =
            [NSSortDescriptor sortDescriptorWithKey:@"header.date" ascending:NO];

            NSMutableArray *combinedMessages =
            [NSMutableArray arrayWithArray:messages];
            [combinedMessages addObjectsFromArray:strongSelf.messages];

            strongSelf.messages =
            [combinedMessages sortedArrayUsingDescriptors:@[sort]];
            [strongSelf.tableView reloadData];
        }];
    }];
}

Now I want to integrate search email functionality in my app. Is there any method available in mailcore2 framework to fetch the searched email with keyword.

Already tried with the link but it was not helpful.

iOS-Is there any method available for fetching CTCoreMessage with specific key words from CTCoreAccount or CTCoreFolder in Mailcore library?