Cargo Features

[dependencies]
io_check = { version = "0.1.2", default-features = false, features = ["backtrace"] }
default = backtrace

The backtrace feature is set by default whenever io_check is added without default-features = false somewhere in the dependency tree.

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features.

backtrace default