text := texts[h]
		for i := 0; i < len(readMakers); i++ {
			for j := 0; j < len(bufreaders); j++ {
				for k := 0; k < len(bufsizes); k++ {
					readmaker := readMakers[i]
					bufreader := bufreaders[j]
					bufsize := bufsizes[k]
					read := readmaker.fn(strings.NewReader(text))
					buf := NewReaderSize(read, bufsize)
					s := bufreader.fn(buf)
					if s != text {
						t.Errorf("reader=%s fn=%s bufsize=%d want=%q got=%q",

	for range numReaders {
		<-clocked
	}
	for range numReaders {
		cunlock <- true
	}
	// Wait for the goroutines to finish.
	for range numReaders {
		<-cdone
	}
}

// Borrowed from rwmutex_test.go
func TestParallelReaders(t *testing.T) {
	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
	doTestParallelReaders(1, 4)
	doTestParallelReaders(3, 4)
	doTestParallelReaders(4, 2)
}

func doTestParallelReaders(numReaders, gomaxprocs int) {
	runtime.GOMAXPROCS(gomaxprocs)
	m := NewLRWMutex()

	clocked := make(chan bool)
	cunlock := make(chan bool)
	cdone := make(chan bool)
	for range numReaders {
		go parallelReader(context.Background(), m, clocked, cunlock, cdone)
	}
	// Wait for all parallel RLock()s to succeed.
	for range numReaders {
		<-clocked
	}
	for range numReaders {

	// Multiple HTTP request handlers updating stats concurrently,
	// while background processes are reading the stats for persistence.
	const numWriters = 100 // Simulate many HTTP request handlers.
	const numReaders = 50  // Simulate background stats readers.
	const opsPerGoroutine = 100

	var wg sync.WaitGroup
	for i := range numWriters {
		wg.Add(1)
		go func(writerID int) {
			defer wg.Done()

func truncateChunkByHalfSigv4(req *http.Request) (*http.Request, error) {
	bufReader := bufio.NewReader(req.Body)
	hexChunkSize, chunkSignature, err := readChunkLine(bufReader)
	if err != nil {
		return nil, err
	}

	newChunkHdr := fmt.Appendf(nil, "%s"+s3ChunkSignatureStr+"%s\r\n",
		hexChunkSize, chunkSignature)
	newChunk, err := io.ReadAll(bufReader)
	if err != nil {
		return nil, err
	}
	newReq := req