The Reject method rejects a pending client connection and
the remote host will see this as the connection being aborted. If
there are no pending client connections at the time, this method will
immediately return with an error indicating that the operation would
cause the thread to block.
This method can only be used inside the OnAccept event,
when the server accepts the pending client connection. If this method
is called outside of an event handler, it will fail.
Rejecting a client connection can cause the client to terminate
abnormally unless it is designed to handle aborted connection
attempts. It is not recommended that you use this method unless you
understand the implications of doing so. To gracefully terminate a
client connection, use the Disconnect method.