Feature flags

[vkurchatkin]

We could wrap new features in feature flags that to could be enabled via command line flag or programmatically. That's what v8 does, Ember.js and maybe others. This way we could ship new features faster and reserve the right to change API for flagged features.

/cc @iojs/owners @iojs/collaborators

[cjihrig]

It would be nice if we could apply the stability index to specific features, instead of at the module level.

[vkurchatkin]

I think basically all flagged features are unstable, everything else conforms to semver

[Fishrock123]

#1159 for the first planned flagged feature

[indutny]

I like it! We should still increment the minors on such stuff, though.

[vkurchatkin]

@indutny of course. This is pretty much how I see it: http://emberjs.com/guides/configuring-ember/feature-flags/

We need some build and runtime infrastructure to make this possible

[chrisdickinson]

A few features have gone in using flags at this point into various branches — uint8array-backed buffers in next, for example. I've opened an issue in the docs-repo-to-be; closing this one for now.

Edit: also, feature flags are a great idea 👏