Cargo Features

groundhog has no features set by default.

[dependencies]
groundhog = { version = "0.2.5", features = ["std", "u128", "instant"] }
std instant?
u128
instant = once_cell, std

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.

once_cell instant?