A transitive dependency is a dependency of a dependency.
So if, for example, mesa3d_util does explicitly use
zerocopy-derive, it should not need to a depend on it.
The package that pulls in transitive should already
include it has a dependency. This provides clearer
methodologies in maintaining Rust code, similiar to
how Cargo.toml handles it.
Reviewed-by: David Gilhooley <djgilhooley.gmail.com>
01bb498e16