System.Net.Http.DelegatingHandler.SetOperationStarted C# (CSharp) Метод

        private void SetOperationStarted()
        {
            CheckDisposed();
            if (_innerHandler == null)
            {
                throw new InvalidOperationException(SR.net_http_handler_not_assigned);
            }
            // This method flags the handler instances as "active". I.e. we executed at least one request (or are
            // in the process of doing so). This information is used to lock-down all property setters. Once a
            // Send/SendAsync operation started, no property can be changed.
            if (!_operationStarted)
            {
                _operationStarted = true;
            }
        }
    }