* - The first request "wins the race".
   * - The second request discovers it "lost the race" and closes the connection it just opened.
   * - The second request uses the coalesced connection from request1.
   * - The coalesced connection is violently closed after servicing the first request.
   * - The second request discovers the coalesced connection is unhealthy just after acquiring it.
   */
  @Test

    checkNotClosed();
    if (target instanceof Flushable) {
      ((Flushable) target).flush();
    }
  }

  @Override
  public void close() throws IOException {
    this.closed = true;
    if (target instanceof Closeable) {
      ((Closeable) target).close();
    }
  }

  @Override
  public Writer append(char c) throws IOException {
    checkNotClosed();
    target.append(c);
    return this;

    for (TestOption option : EnumSet.of(OPEN_THROWS, READ_THROWS, CLOSE_THROWS)) {
      TestCharSource failSource = new TestCharSource(STRING, option);
      TestCharSink okSink = new TestCharSink();
      assertThrows(IOException.class, () -> failSource.copyTo(okSink));
      // ensure writer was closed IF it was opened (depends on implementation whether or not it's

        messageBuffer.readAndWriteUnsafe(maskCursor!!)
        maskCursor.seek(0L)
        toggleMask(maskCursor, maskKey)
        maskCursor.close()
      }
    }

    sinkBuffer.write(messageBuffer, dataSize)
    sink.emit()
  }

  override fun close() {
    messageDeflater?.close()
  }

    Stream<String> streamB = Stream.of("b").onClose(closeCountB::incrementAndGet);
    Stream<String> concatenated =
        Stream.<Stream<String>>of(Stream.of("a"), streamB, Stream.empty(), Stream.of("c", "d"))
            .flatMap(x -> x);
    assertThat(concatenated).containsExactly("a", "b", "c", "d").inOrder();
    concatenated.close();
    // even without close, see doc for flatMap

    TestInputStream in = new TestInputStream(new ByteArrayInputStream(new byte[10]));
    assertFalse(in.closed());
    sink.writeFrom(in);
    assertFalse(in.closed());
  }

  public void testClosesOnErrors_copyingFromByteSourceThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, READ_THROWS, CLOSE_THROWS)) {
      TestByteSource failSource = new TestByteSource(new byte[10], option);

permissions:
  contents: read

jobs:
  stale:
    permissions:
      issues: write  # for actions/stale to close stale issues
      pull-requests: write  # for actions/stale to close stale PRs
    runs-on: ubuntu-latest
    env:
      ACTIONS_STEP_DEBUG: true
    steps:
    - name: Close Stale Issues
      uses: actions/stale@v8
      with:
        repo-token: ${{ secrets.GITHUB_TOKEN }}

	return &fakeNs{closed: &atomic.Bool{}, fd: fd, inode: inode}
}

// Fd returns the file descriptor
func (f *fakeNs) Fd() uintptr {
	return f.fd
}

func (f *fakeNs) Inode() uint64 {
	return f.inode
}

// Close simulates closing the file descriptor and returns nil for no error
func (f *fakeNs) Close() error {
	f.closed.Store(true)
	return nil
}

func fakeFs() fs.FS {

    if (connectionUser.candidateConnection() != null) {
      check(toClose == null)
      return ReusePlan(candidate)
    }

    // The call's connection was released.
    toClose?.closeQuietly()
    connectionUser.connectionReleased(candidate)
    connectionUser.connectionConnectionReleased(candidate)
    if (toClose != null) {
      connectionUser.connectionConnectionClosed(candidate)

}

type Netns interface {
	NetnsFd
	Inode() uint64
}
type NetnsCloser interface {
	io.Closer
	Netns
}

type NetnsWithFd struct {
	netns io.Closer
	fd    uintptr
	inode uint64
}

func (n *NetnsWithFd) Close() error {
	if n.netns == nil {
		return nil
	}

	ret := n.netns.Close()
	// set fd to invalid value, so if something uses it by mistake it will err
	uintZero := uintptr(0)