I'm not sure there's a realistic alternative. If you need to generate a key then it has to happen somehow on unsupported platforms. You can check Enabled() if you need to know and intend to do something different but I assume most of the time you run the same function either way you'd just prefer to opt into secret mode if it's available.
This is not what secret.Enabled() means. But it probably illustrates that the function needs to be renamed already. Here's what the doc comment says:
// Enabled reports whether Do appears anywhere on the call stack.
In other words, it is just a way of checking that you are indeed running inside the context of some secret.Do call; it doesn't guarantee that secret.Do is actually offering the protection you may desire.
One of the goals here is to make it easy to identify existing code which would benefit from this protection and separate that code from the rest. That code is going to run anyway, it already does so today.
