Cargo Features

SP800-185 has no features set by default.

[dependencies]
sp800-185 = { version = "0.2.0", features = ["parallelhash"] }
parallelhash = rayon

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

rayon parallelhash?

Enables rayon ^0.9