ssa: cache types named in runtime

_demo/async/timeout/timeout.go

@@ -0,0 +1,16 @@
+package timeout
+
+import (
+	"time"
+
+	"github.com/goplus/llgo/_demo/async/async"
+)
+
+func Timeout(d time.Duration) async.Future[async.Void] {
+	return async.Async(func(resolve func(async.Void)) {
+		go func() {
+			time.Sleep(d)
+			resolve(async.Void{})
+		}()
+	})
+}