Cargo Features

get-size2 has no features set by default.

[dependencies]
get-size2 = { version = "0.1.2", features = ["derive"] }
derive = get-size-derive2

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.

get-size-derive2 derive?