pub fn on_runtime(runtime: Runtime) -> Self {
        Self {
            layers: Vec::new(),
            runtime,
        }
    }
Creates a new builder with the provided Tokio runtime.
This method can be used if asynchronous tasks must be performed before the service is built.

However, it is not recommended to use this method to spawn any tasks that will not be managed
by the service itself, so whenever it can be avoided, using [`ZkStackServiceBuilder::new`] is preferred.
core/lib/node_framework/src/service/mod.rs