Close Scheduler in the delay example (#39)

Author: mathetake

go/delay.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"fmt"
 	"strconv"
 	"time"
 
@@ -35,20 +34,20 @@ func (p *delayFilter) RequestHeaders(e gosdk.EnvoyHttpFilter, endOfStream bool)
 	// Check if the headers contain the "do-delay" header to trigger the delay.
 	if _, ok := e.GetRequestHeader("do-delay"); !ok {
 		// If the header is not present, continue the request processing.
-		fmt.Println("gosdk: RequestHeaders, do-delay header not found, continuing request processing")
 		return gosdk.RequestHeadersStatusContinue
 	}
 
 	schduler := e.NewScheduler()
 	now := time.Now()
 	p.onRequestHeaders = now
 	go func() {
+		// Scheduler must be closed to avoid memory leaks.
+		defer schduler.Close()
 		// Simulate some delay.
 		time.Sleep(2 * time.Second)
 		// Commit the event to continue the request processing.
 		schduler.Commit(0)
 	}()
-	fmt.Printf("gosdk: RequestHeaders, delaying request processing for 2 seconds at %s\n", now)
 	return gosdk.RequestHeadersStatusStopIteration
 }
 
@@ -57,7 +56,6 @@ func (p *delayFilter) Sheduled(e gosdk.EnvoyHttpFilter, eventID uint64) {
 	if eventID != 0 {
 		panic("unexpected eventID in Sheduled: " + strconv.Itoa(int(eventID)))
 	}
-	fmt.Println("gosdk: Sheduled, continuing request processing after delay")
 	p.delayLapsed = time.Since(p.onRequestHeaders)
 	// We can insert some headers at this phase.
 	e.SetRequestHeader("delay-filter-on-scheduled", []byte("yes"))

go/gosdk/gosdk.go

@@ -80,6 +80,8 @@ type Scheduler interface {
 	// Commit commits the event to the Envoy filter on the correct worker thread.
 	// The eventID is a unique identifier for the event, and it can be used to distinguish between different events.
 	Commit(eventID uint64)
+	// Close closes the scheduler and releases any resources associated with it.
+	// This must be called when the scheduler is no longer needed to avoid memory leaks.
 	Close()
 }
 
@@ -99,7 +101,8 @@ type HttpFilter interface {
 	ResponseBody(e EnvoyHttpFilter, endOfStream bool) ResponseBodyStatus
 	// TODO: add ResponseTrailers support.
 
-	// Scheuled is called when the filter is scheduled to run.
+	// Scheuled is called when the filter is scheduled to run on the Envoy worker thread.
+	// Such event is created via [Scheduler.Commit] and the eventID is the unique identifier for the event.
 	Sheduled(e EnvoyHttpFilter, eventID uint64)
 
 	// Destroy is called when the stream is destroyed.