rc   io.ReadCloser
	done chan struct{}
}

func (c *closeNotifier) Read(p []byte) (n int, err error) {
	n, err = c.rc.Read(p)
	if err != nil {
		if c.done != nil {
			xioutil.SafeClose(c.done)
			c.done = nil
		}
	}
	return n, err
}

func (c *closeNotifier) Close() error {
	if c.done != nil {
		xioutil.SafeClose(c.done)
		c.done = nil
	}
	return c.rc.Close()
}

func (writer *messageWriter) Finish(bytesScanned, bytesProcessed int64) error {
	select {
	case <-writer.doneCh:
		return fmt.Errorf("messageWriter is done")
	default:
		writer.finBytesScanned = bytesScanned
		writer.finBytesProcessed = bytesProcessed
		close(writer.payloadCh)
		// Wait until the `start` go-routine is done.
		<-writer.doneCh
		return nil
	}
}

		return ps.Participating && ps.Info.Status == rebalStarted
	}
	return false
}

func (z *erasureServerPools) rebalanceBuckets(ctx context.Context, poolIdx int) (err error) {
	doneCh := make(chan error, 1)
	defer xioutil.SafeClose(doneCh)

	// Save rebalance.bin periodically.
	go func() {
		// Update rebalance.bin periodically once every 5-10s, chosen randomly

		size := actualSz
		if i.heal.enabled {
			done := globalScannerMetrics.time(scannerMetricHealCheck)
			size = i.applyHealing(ctx, objAPI, oi)
			done()

			if healDeleteDangling {
				done := globalScannerMetrics.time(scannerMetricCleanAbandoned)
				err := objAPI.CheckAbandonedParts(ctx, i.bucket, i.objectPath(), madmin.HealOpts{Remove: healDeleteDangling})
				done()
				if err != nil {

FastAPI bu dönüş tipini şunlar için kullanır:

* Dönen veriyi **doğrulamak** (validate).
    * Veri geçersizse (ör. bir field eksikse), bu *sizin* uygulama kodunuzun bozuk olduğu, olması gerekeni döndürmediği anlamına gelir; bu yüzden yanlış veri döndürmek yerine server error döner. Böylece siz ve client’larınız, beklenen veri ve veri şeklinin geleceğinden emin olabilirsiniz.

        crawlerStatsHelper.done(key);
        logger.info(localLogMsg.get());
        String[] values = localLogMsg.get().split("\t");
        assertEquals(3, values.length);
        assertEquals("url:test", values[0]);
        assertTrue(values[1].startsWith("time:"));
        assertTrue(values[2].startsWith("done:"));

        localLogMsg.remove();
        crawlerStatsHelper.done(key);
        assertNull(localLogMsg.get());

	ctx, done, err := p.TrackDiskHealth(ctx, storageMetricListVols, "/")
	if err != nil {
		return nil, err
	}
	defer done(0, &err)

	return p.storage.ListVols(ctx)
}

func (p *xlStorageDiskIDCheck) StatVol(ctx context.Context, volume string) (vol VolInfo, err error) {
	ctx, done, err := p.TrackDiskHealth(ctx, storageMetricStatVol, volume)
	if err != nil {
		return vol, err
	}
	defer done(0, &err)

        assertFalse(cos.done);
        assertTrue(cos.isInMemory());
        cos.close();
        assertFalse(cos.done);
    }

    @Test
    public void inFile() throws IOException {
        ContentOutputStream cos = new ContentOutputStream(10, Curl.tmpDir);
        cos.write(new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 });
        assertFalse(cos.done);
        assertFalse(cos.isInMemory());

					done = true
				}
			}
		case <-ctx.Done():
			// Capture timedout locks as failed or took too long
			locksFailed++
			if locksFailed > tolerance {
				// We know that we are not going to get the lock anymore,
				// so exit out and release any locks that did get acquired
				done = true
			}
		}

		if done {
			break
		}
	}

				ObjectInfo: result.Item,
			})
			pushToExpire()
		case <-ctx.Done():
			done = true
		}
		if done {
			break
		}
	}

	if context.Cause(ctx) != nil {
		xioutil.SafeClose(expireCh)
		return context.Cause(ctx)
	}
	pushToExpire()
	// Send any remaining objects downstream
	if len(toDel) > 0 {
		select {
		case <-ctx.Done():
		case expireCh <- toDel:
		}
	}