Add example for ResultWriter

example_test.go

@@ -5,6 +5,7 @@
 package asynq_test
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"os"
@@ -113,3 +114,20 @@ func ExampleParseRedisURI() {
 	// localhost:6379
 	// 10
 }
+
+func ExampleResultWriter() {
+	// ResultWriter is only accessible in Handler.
+	h := func(ctx context.Context, task *asynq.Task) error {
+		// .. do task processing work
+
+		res := []byte("task result data")
+		n, err := task.ResultWriter().Write(res) // implements io.Writer
+		if err != nil {
+			return fmt.Errorf("failed to write task result: %v", err)
+		}
+		log.Printf(" %d bytes written", n)
+		return nil
+	}
+
+	_ = h
+}