Added Extra Opts + Example + ExceedExpected Option

Signed-off-by: Sherif Abdel-Naby <sherifabdlnaby@gmail.com>

examples/schedule-warn-expected/main.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"fmt"
+	"github.com/sherifabdlnaby/sched"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+)
+
+func main() {
+
+	fixed2s, err := sched.NewFixed(2 * time.Second)
+	if err != nil {
+		panic(fmt.Sprintf("invalid interval: %s", err.Error()))
+	}
+
+	job := func() {
+		log.Println("Doing some work...")
+		time.Sleep(1 * time.Second)
+		log.Println("Finished Work.")
+	}
+
+	// Create Schedule
+	schedule := sched.NewSchedule("fixed2s", fixed2s, job, sched.WithLogger(sched.DefaultLogger()), sched.WithExpectedRunTime(500*time.Millisecond))
+
+	// Start Schedule
+	schedule.Start()
+
+	// Listen to CTRL + C And indefintly wait shutdown.
+	signalChan := make(chan os.Signal, 1)
+	signal.Notify(signalChan, syscall.SIGTERM, syscall.SIGINT, syscall.SIGQUIT)
+	_ = <-signalChan
+
+	// Stop before shutting down.
+	schedule.Stop()
+
+	return
+}