Stopping use of timer based cleanup logic for MRD (#2931)

Stopping use of timer based cleanup logic for MRD. Have minimized code changes so that reverting change back is easy.

Author: abhishek10004

internal/gcsx/multi_range_downloader_wrapper.go

@@ -105,7 +105,10 @@ func (mrdWrapper *MultiRangeDownloaderWrapper) DecrementRefCount() (err error) {
 
 	mrdWrapper.refCount--
 	if mrdWrapper.refCount == 0 {
-		mrdWrapper.cleanupMultiRangeDownloader()
+		mrdWrapper.Wrapped.Close()
+		mrdWrapper.Wrapped = nil
+		// TODO (b/391508479): Start using cleanup function when MRD recreation is handled
+		// mrdWrapper.cleanupMultiRangeDownloader()
 	}
 	return
 }

internal/gcsx/multi_range_downloader_wrapper_test.go

@@ -80,14 +80,12 @@ func (t *mrdWrapperTest) Test_IncrementRefCount_CancelCleanup() {
 	err := t.mrdWrapper.DecrementRefCount()
 
 	assert.Nil(t.T(), err)
-	assert.NotNil(t.T(), t.mrdWrapper.cancelCleanup)
-	assert.NotNil(t.T(), t.mrdWrapper.Wrapped)
+	assert.Nil(t.T(), t.mrdWrapper.Wrapped)
 
 	t.mrdWrapper.IncrementRefCount()
 
 	assert.Equal(t.T(), finalRefCount, t.mrdWrapper.refCount)
 	assert.Nil(t.T(), t.mrdWrapper.cancelCleanup)
-	assert.NotNil(t.T(), t.mrdWrapper.Wrapped)
 }
 
 func (t *mrdWrapperTest) Test_DecrementRefCount_ParallelUpdates() {
@@ -115,8 +113,7 @@ func (t *mrdWrapperTest) Test_DecrementRefCount_ParallelUpdates() {
 	wg.Wait()
 
 	assert.Equal(t.T(), finalRefCount, t.mrdWrapper.GetRefCount())
-	assert.NotNil(t.T(), t.mrdWrapper.Wrapped)
-	assert.NotNil(t.T(), t.mrdWrapper.cancelCleanup)
+	assert.Nil(t.T(), t.mrdWrapper.Wrapped)
 	// Waiting for the cleanup to be done.
 	time.Sleep(t.mrdTimeout + time.Millisecond)
 	assert.Nil(t.T(), t.mrdWrapper.Wrapped)