Cargo Features

rand_isaac has no features set by default.

[dependencies]
rand_isaac = { version = "0.3.0", features = ["serde1", "serde_derive"] }
serde1 = serde

Enables serde1 of rand_core

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.

serde serde1?
serde_derive implicit feature

Enables serde_derive

Not a direct dependency but required to boost the minimum version: