add support for data waiters interface

examples/datawaiters/main.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2018 Versity Software, Inc.
+//
+// Use of this source code is governed by a BSD-3-Clause license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"time"
+
+	"github.com/versity/scoutfs-go"
+)
+
+func main() {
+	if len(os.Args) != 2 || os.Args[1] == "-h" {
+		fmt.Fprintln(os.Stderr, "usage:", os.Args[0], "<scoutfs mount point>")
+		os.Exit(1)
+	}
+
+	f, err := os.Open(os.Args[1])
+	if err != nil {
+		log.Fatalf("Open %v: %v", os.Args[1], err)
+	}
+	defer f.Close()
+
+	w := scoutfs.NewWaiters(f)
+
+	for {
+		ents, err := w.Next()
+		if err != nil {
+			log.Fatalf("next(): %v", err)
+		}
+		if ents == nil {
+			time.Sleep(time.Second)
+			continue
+		}
+		for _, ent := range ents {
+			log.Printf("%+v", ent)
+		}
+	}
+}