Cargo Features

futures-core-preview = { version = "0.3.0-alpha.19", default-features = false, features = ["std", "alloc", "unstable", "cfg-target-has-atomic"] }
default = std

The std feature is set by default whenever futures-core-preview is added without default-features = false somewhere in the dependency tree.

std default = alloc
alloc std

Affects future::BoxFuture, future::LocalBoxFuture, stream::BoxStream, stream::LocalBoxStream


Unstable features These features are outside of the normal semver guarantees and require the unstable feature as an explicit opt-in to unstable API.