* Defaults for file audit logging backend in batch mode changed: ([#67223](https://github.com/kubernetes/kubernetes/pull/67223), [@tallclair](https://github.com/tallclair))
    * Logs are written 1 at a time (no batching)
    * Only a single writer process (lock contention)

- Kubeadm: fix a regression where the KubeletConfiguration is not properly downloaded during "kubeadm upgrade" commands from the kube-system/kubelet-config ConfigMap, resulting in the local '/var/lib/kubelet/config.yaml' file being written as a defaulted config. ([#124497](https://github.com/kubernetes/kubernetes/pull/124497), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

## Dependencies

### Added
_Nothing has changed._

     * @throws IOException If the model could not be serialized.
     */
    void write(File output, Map<String, Object> options, Model model) throws IOException;

    /**
     * Writes the supplied model to the specified character writer. The writer will be automatically closed before the
     * method returns.
     *
     * @param output The writer to serialize the model to, must not be {@code null}.

package cmd

import (
	"context"
	"fmt"
	"io"
)

// Writes to multiple writers
type multiWriter struct {
	writers     []io.Writer
	writeQuorum int
	errs        []error
}

// Write writes data to writers.
func (p *multiWriter) Write(ctx context.Context, blocks [][]byte) error {
	for i := range p.writers {
		if p.errs[i] != nil {
			continue
		}

     * @throws IOException If the settings could not be serialized.
     */
    void write(File output, Map<String, Object> options, Settings settings) throws IOException;

    /**
     * Writes the supplied settings to the specified character writer. The writer will be automatically closed before
     * the method returns.
     *
     * @param output The writer to serialize the settings to, must not be {@code null}.

                throw new DictionaryException("Failed to write: " + oldItem + " -> " + item, e);
            }
        }

        /**
         * Writes a line to the new file.
         *
         * @param line The line to write.
         */
        public void write(final String line) {
            try {
                writer.write(line);
                writer.write(Constants.LINE_SEPARATOR);

Regular Reads will block until data is available, but not wait for a full buffer. 
Writes will block until there is space available and writes bigger than the buffer will wait for reads to make space.

`TryRead` and `TryWrite` are still available for non-blocking reads and writes.

To signify the end of the stream, close the ring buffer from the writer side with `rb.CloseWriter()`

                try {
                    writer.write(s);
                    writer.write('\n');
                } catch (final IOException e) {
                    throw new IORuntimeException(e);
                }
            });
        } catch (final Exception e) {
            logger.warn("Failed to write thread dump: file={}", file, e);
        }
    }

    /**

### Dockershim deprecation

Docker as an underlying runtime is being deprecated. Docker-produced images will continue to work in your cluster with all runtimes, as they always have.
The Kubernetes community [has written a blog post about this in detail](https://blog.k8s.io/2020/12/02/dont-panic-kubernetes-and-docker/) with [a dedicated FAQ page for it](https://blog.k8s.io/2020/12/02/dockershim-faq/).

### External credential provider for client-go

 */
@Deprecated(since = "4.0.0")
public interface ToolchainsWriter {

    /**
     * Writes the supplied toolchains to the specified character writer. The writer will be automatically closed before
     * the method returns.
     *
     * @param output The writer to serialize the toolchains to, must not be {@code null}.