System.Net.Http.HttpClient.SetOperationStarted C# (CSharp) Method

        private void SetOperationStarted()
        {
            // This method flags the HttpClient 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;
            }
        }