If you browse the source, the go scheduler has complexities to deal with that tokio doesn't as well. The thread pool is unified between worker threads & blocking threads. Go also does goroutine preemption via signaling/SuspendThread + a background monitor thread called sysmon. Go does garbage collection and the tracing/race-detection/semantics are tightly coupled to both its allocator and it's scheduler. Go also exposes and maintains its entire standard library which includes an http client/server (tokio the org maintains their own as hyper but its separated from tokio the runtime). It can be fair to argue that Go is just as "swiss-army-knife" of a system as tokio.