Cargo Features

[dependencies]
tracing-core = { version = "0.1.33", default-features = false, features = ["std", "valuable"] }
default = std

These default features are set whenever tracing-core is added without default-features = false somewhere in the dependency tree.

Enables std of optional valuable

valuable:

Provide impls for common standard library types like Vec<T> and HashMap<K, V>.

std default = once_cell

Affects dispatcher::DefaultGuard, dispatcher::with_default, dispatcher::set_default, dispatcher::get_default, dispatcher::get_current, field::Visit.record_error

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 std
valuable tracing_unstable implicit feature

Enables valuable

valuable:

Object-safe value inspection, used to pass un-typed structured data across trait-object boundaries

Affects field::Visit.record_value, field::valuable