asyncio: demo & test

x/async/_demo/gendemo/gendemo.go

@@ -1,21 +1,26 @@
 package main
 
-import "github.com/goplus/llgo/x/async"
+import (
+	"fmt"
+
+	"github.com/goplus/llgo/x/async"
+)
 
 func GenInts() (co *async.Promise[int]) {
-	print("1")
+	println("gen: 1")
 	co.Yield(1)
-	print("2")
+	println("gen: 2")
 	co.Yield(2)
-	print("3")
+	println("gen: 3")
 	co.Yield(3)
-	print("4")
 	return
 }
 
 func main() {
 	co := GenInts()
 	for !co.Done() {
-		print(co.Next())
+		fmt.Printf("got: %v\n", co.Value())
+		co.Next()
 	}
+	fmt.Printf("done\n")
 }