Detect null stream on I2PConnect

I2PTunnel.cpp

@@ -1,3 +1,4 @@
+#include <cassert>
 #include "base64.h"
 #include "Log.h"
 #include "Destination.h"
@@ -35,11 +36,14 @@ namespace client
 	}	
 
 	void I2PTunnelConnection::I2PConnect (const uint8_t * msg, size_t len)
+	{
+		if (m_Stream)
 		{
 			if (msg)
 				m_Stream->Send (msg, len); // connect and send
 			else	
 				m_Stream->Send (m_Buffer, 0); // connect
+		}
 		StreamReceive ();
 		Receive ();
 	}