Define asynchronous conversation snapshots for PM clients

src/dm/dm_core.h

@@ -120,6 +120,8 @@ struct dm_messages_req {
     char conv_id[64];
 };
 void dm_messages_trampoline(void* arg);
+struct dm_conversations_req { struct UTUN_INSTANCE* inst; };
+void dm_conversations_trampoline(void* arg);
 
 #ifdef __cplusplus
 }