Cargo Features

HyperId has no features set by default.

[dependencies]
hyperid = { version = "2.3.1", features = ["url_safe"] }
url_safe = base64

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.

base64 url_safe?