OnSTAT is a TIdPOP3ServerNoParamEvent property that represents the event handler signalled when a threaded client connection performs the POP3 STAT command verb. 

OnSTAT allows the server to implement processing required to generate a status listing for the maildrop for for the client connection. 

To simplify POP3 client parsing, the POP3 server is required to use a common format for drop listings. The positive response consists of "+OK" followed by a single space, the number of messages in the maildrop, a single space, and the size of the maildrop in octets. Additional server-dependent information may be included in the drop listing, but it is not encouraged. The drop listing is terminated by the CRLF pair. 

Messages marked for deletion should not be included in the message count or total message size for the maildrop. 

OnSTAT is triggered by the command event handler that implements the POP3 STAT command for the client context. OnSTAT is not triggered for a client connection where TIdPOP3ServerThread.State contains a value other than Trans. 

OnSTAT is responsible for writing the positive POP3 response to the client connection; Negative POP3 responses are written by the STAT command handler when TIdPOP3ServerThread.State contains a value other than Trans or the OnSTAT event handler has not been assigned.

TIdPOP3ServerNoParamEvent TIdPOP3ServerThread.State TIdCommandHandlers TIdCommandHandler TIdCommand