public EhrExtract Convert(OutViewModel model, string name, string systemId) { if (model == default) { throw new ArgumentNullException(nameof(model)); } if (_outToEHRConverter == default) { _locker.EnterWriteLock(); if (_outToEHRConverter == default) { _outToEHRConverter = new OutToEHRConverter(EhrManager); } _locker.ExitWriteLock(); } return(_outToEHRConverter.Convert(model, name, systemId)); }