(cobra client) can subscribe with a position

ixcobra/ixcobra/IXCobraConnection.cpp

@@ -565,6 +565,7 @@ namespace ix
 
     void CobraConnection::subscribe(const std::string& channel,
                                     const std::string& filter,
+                                    const std::string& position,
                                     SubscriptionCallback cb)
     {
         // Create and send a subscribe pdu
@@ -576,6 +577,11 @@ namespace ix
             body["filter"] = filter;
         }
 
+        if (!position.empty())
+        {
+            body["position"] = position;
+        }
+
         Json::Value pdu;
         pdu["action"] = "rtm/subscribe";
         pdu["body"] = body;

ixcobra/ixcobra/IXCobraConnection.h

@@ -98,6 +98,7 @@ namespace ix
         // message arrives.
         void subscribe(const std::string& channel,
                        const std::string& filter = std::string(),
+                       const std::string& position = std::string(),
                        SubscriptionCallback cb = nullptr);
 
         /// Unsubscribe from a channel