Generally none of the email protocols (IMAP, POP3) allow bulk email download, that would be significantly faster than downloading emails one by one.
Basic email download sample looks like this:
using(Imap imap = new Imap())
{
imap.Connect("imap.server.com"); // or ConnectSSL for SSL
imap.UseBestLogin("user", "password");
imap.SelectInbox();
List<long> uids = imap.Search(Flag.Unseen);
foreach (long uid in uids)
{
IMail email = new MailBuilder()
.CreateFromEml(imap.GetMessageByUID(uid));
Console.WriteLine(email.Subject);
}
imap.Close();
}
Please note that entire emails is downloaded, this includes all attachments.
Here's the article that shows how to download new emails using IMAP:
https://www.limilabs.com/blog/get-new-emails-using-imap
You can download most common email fields, like subject, from, to and others using following approach - it is much faster, but doesn't download entire email message and attachments:
https://www.limilabs.com/blog/get-email-information-from-imap-fast