I've tried submitting this to the bug list at
http://www.nevrona.com/Indy/BugReport.html but it's not working.  It says
there's some sort of socket error (!!!!).

TIdTCPConnection.WriteBuffer seems to be the cause of a virtual memory leak
if a null byte is sent through it.

void __fastcall TSimpleThread::Write(AnsiString Msg)
{
    char    Terminator = 0;

    // Client is a TIdTCPClient pointer

    try {
        Client->Write(Msg);
        Client->WriteBuffer(&Terminator, 1 , true);
    }
    catch(...) {
        // socket probably disconnected
    }

Memproof shows the virtual memory rising and rising until after several days
there isn't much left :)
There is no resource leak at all if I don't send a 0 byte.  I've tried:

Client->WriteBuffer(&Terminator, 1 , true); (where Terminator is a 0 byte)
and Client->Write(CHAR0);
and Client->Write(Msg + CHAR0);

Oops... I'm totally wrong.  That 0 is triggering a response from the server
which then gets put through the OpenXML parser.  It looks like the XTML
parser has the memory leak.

Sorry!