sync method
Implementation
Future<int> sync(int count,MesiboSyncListener listener) async{if(0== _session){_session= await Mesibo.getInternal().createReadSession(_profile,_flags,_threadId,_query) as int;MesiboReadSession._addSession(_session,this);}
_syncListener= listener;return await Mesibo.getInternal().ReadSessionSync(_session,count) as int;}