fillReq:   make(chan struct{}),
		fillReady: make(chan int64),
	}

	go func() {
		var rpos int64 // total bytes read into buffer

		defer func() {
			atomic.StoreInt64(&sr.end, rpos)
			close(sr.fillReady)
		}()

		for range sr.fillReq {
		scan:
			n, err := r.Read(sr.nbuf[:])

			if n == 0 {
				switch err {
				case io.EOF: // reader is exhausted
					return

}

// RLock holds a read lock on lm.
//
// If one or more read lock are already in use, it will grant another lock.
// Otherwise the calling go routine blocks until the mutex is available.
func (lm *LRWMutex) RLock() {
	const isWriteLock = false
	lm.lockLoop(context.Background(), lm.id, lm.source, 1<<63-1, isWriteLock)
}

// GetRLock tries to get a read lock on lm before the timeout occurs.

// reads in Scanner.Scan.
type slowReader struct {
	max int
	buf io.Reader
}

func (sr *slowReader) Read(p []byte) (n int, err error) {
	if len(p) > sr.max {
		p = p[0:sr.max]
	}
	return sr.buf.Read(p)
}

// genLine writes to buf a predictable but non-trivial line of text of length
// n, including the terminal newline and an occasional carriage return.

And it's possible that for your use case, the solution is in one of them.

///

## Read the Tutorial first { #read-the-tutorial-first }

You could still use most of the features in **FastAPI** with the knowledge from the main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank}.

  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#maintained
  schedule:
    - cron: '45 9 * * 0'
  push:
    branches: [ "master" ]

# Declare default permissions as read only.
permissions: read-all

jobs:
  analysis:
    name: Scorecard analysis
    runs-on: ubuntu-latest
    permissions:
      # Needed to upload the results to code-scanning dashboard.
      security-events: write

    class IntegrationTests {

        @Test
        @DisplayName("Should handle complete read-write cycle")
        void testCompleteReadWriteCycle() throws SMBProtocolDecodingException {
            // Given
            byte[] writeBuffer = new byte[100];
            byte[] readBuffer = new byte[100];

            // Prepare valid read buffer
            SMBUtil.writeInt2(4, readBuffer, 10);

                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                    "tags": ["items"],
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                }
            },
            "/users/": {
                "get": {
                    "responses": {
                        "200": {

    stream = io.BytesIO(b"data")
    file = UploadFile(filename="file", file=stream, size=4)
    assert await file.read() == b"data"
    assert file.size == 4
    await file.write(b" and more data!")
    assert await file.read() == b""
    assert file.size == 19
    await file.seek(0)
    assert await file.read() == b"data and more data!"

            beg_idx = (beg_idx + 1) % pipe_buf.length;
        }
        return result;
    }

    @Override
    public int read(final byte[] b) throws IOException {
        return read(b, 0, b.length);
    }

    @Override
    public int read(final byte[] b, int off, final int len) throws IOException {
        int result = -1;
        int i;

        if (len <= 0) {
            return 0;

var ErrAlreadyLocked = errors.New("file already locked")

// RLockedFile represents a read locked file, implements a special
// closer which only closes the associated *os.File when the ref count.
// has reached zero, i.e when all the readers have given up their locks.
type RLockedFile struct {
	*LockedFile
	mutex sync.Mutex
	refs  int // Holds read lock refs.
}

// IsClosed - Check if the rlocked file is already closed.