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;
}
}
}