Cargo Features

not-so-fast has no features set by default.

[dependencies]
not-so-fast = { version = "0.2.0", features = ["derive", "serde"] }
derive = not-so-fast-derive

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.

not-so-fast-derive derive?
serde implicit feature

Enables serde

serde:

A generic serialization/deserialization framework