Currently, performance-sensitive parts are no longer heavily dependent on the runtime. However, we haven't been able to remove the runtime yet because there are still the following areas that require it:

1. Async interfaces like fetch may need to spawn a detached task, which still relies on the runtime's spawn.
2. Some background workers require spawning coroutines.
3. The psycn + thread pool IO engine is currently using Tokio's thread pool. In theory, it's independent from the runtime, but some work still needs to be separated.

Perhaps a "spawnable" abstraction could be created to support both Tokio/pthread and other execution modes.