is_sync_running() added

Adapter.cc

@@ -116,5 +116,10 @@ namespace pEp {
             }
             session(release);
         }
+
+        bool is_sync_running()
+        {
+            return _sync_thread != nullptr;
+        }
     }
 }

Adapter.hh

@@ -43,6 +43,8 @@ namespace pEp {
         // injects a NULL event into sync_event_queue to denote sync thread to shutdown,
         // and joins & removes the sync thread
         void shutdown();
+
+        bool is_sync_running();
     }
 }