Session not explicitly handling DoNotSend from Application::ToApp

[cbusbey]

From IApplication,

        /// 

        /// This is a callback for application messages that you are sending to a
        /// counterparty. If you throw a DoNotSend exception in this function, the
        /// application will not send the message. This is mostly useful if the
        /// application has been asked to resend a message such as an order that is
        /// no longer relevant for the current market. Messages that are being resent
        /// are marked with the PossDupFlag in the header set to true; If a DoNotSend
        /// exception is thrown and the flag is set to true, a sequence reset will be
        /// sent in place of the message. If it is set to false, the message will
        /// simply not be sent. You may add fields before an application message
        /// before it is sent out.
        /// 
        /// 
        /// 
        /// throw this to abort sending the message
        void ToApp(Message message, SessionID sessionId);

Note however that Session does not explicitly handle DoNotSend Exceptions.

https://github.com/connamara/quickfixn/blob/master/QuickFIXn/Session.cs#L1585

A try/catch should surround this call and return false if DoNotSend is thrown by the Application.