# What is this crate used for?

This is a dependency of the `tracing` crate.

# Are there any use restrictions? i.e. only for development hosts

No.

# What differs from upstream?

We vendor the exact crate but remove the included copies of spin and lazy_static which are only
used in no_std environments. If upstream stops shipping vendored code with different licenses
which won't be used in our build from the main crate, we can un-fork. This should happen when both
https://github.com/matklad/once_cell/issues/61 and https://github.com/tokio-rs/tracing/issues/1165
are resolved.

# Are there any restrictions to how it should be rolled?

No.

# Is there anything else which makes this dependency "special"?

No.