This function only marks the message for deletion. The message
is not actually deleted until the mailbox is expunged or another
mailbox is selected. This function will return an error if the
current mailbox is in read-only mode, such as if it was selected
using the ImapExamineMailbox function.
It is important to note that unlike the POP3 protocol, a message
that is marked for deletion is still accessible on the IMAP server
until the mailbox is expunged. This means, for example, that a
deleted message can still be retrieved using the
ImapGetMessage function.
To determine if a message has been marked for deletion, use the
ImapGetMessageFlags function and check if the
IMAP_FLAG_DELETED bit flag has been set. To list all of the deleted
messages in the current mailbox, use the
ImapGetDeletedMessages function.
To remove the deletion flag from the message, use the
ImapUndeleteMessage function. To prevent all messages in the
current mailbox from being expunged, use the
ImapReselectMailbox function to reset the current mailbox
state.