Structure feature flags strategically

Design feature flags to minimize dependency bloat while maximizing flexibility for users. Each optional dependency should be tied to a specific feature flag, allowing users to enable only the functionality they need.

Key practices:

1. Express dependencies between features explicitly in Cargo.toml
2. Create granular feature flags for optional dependencies
3. Use conditional compilation for platform or feature-specific code
4. Consider feature organization when adding new functionality

For example, instead of requiring a dependency for all users:

# Avoid this approach - forces dependency on all users
rt = ["tokio/rt", "tokio/sync", "futures-util", "hashbrown"]

Use a more targeted approach:

# Better approach - separate optional functionality
rt = ["tokio/rt", "tokio/sync", "futures-util"]
join-map = ["rt", "hashbrown"]

For platform-specific features, use appropriate conditional compilation:

# For platform-specific features
[target.'cfg(all(target_os = "linux", feature = "rt"))'.dependencies]
# Linux-specific dependencies here

When organizing features, aim for a balance between granularity and usability, with a “full” feature that enables everything for convenience.