int slen = s.length();

    // Get a destination buffer and setup some loop variables.
    char[] dest = Platform.charBufferFromThreadLocal();
    int destSize = dest.length;
    int destIndex = 0;
    int lastEscape = 0;

    // Loop through the rest of the string, replacing when needed into the
    // destination buffer, which gets grown as needed as well.
    for (; index < slen; index++) {

  static char[] charBufferFromThreadLocal() {
    // requireNonNull accommodates Android's @RecentlyNullable annotation on ThreadLocal.get
    return requireNonNull(DEST_TL.get());
  }

  /**
   * A thread-local destination buffer to keep us from creating new buffers. The starting size is
   * 1024 characters. If we grow past this we don't put it back in the threadlocal, we just keep
   * going and grow as needed.
   */

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.nio.charset.Charset;

/**
 * A destination to which characters can be written, such as a text file. Unlike a {@link Writer}, a
 * {@code CharSink} is not an open, stateful stream that can be written to and closed. Instead, it

      }
    }

    private E transferElement(Stack<E> source, Stack<E> destination) {
      if (source.isEmpty()) {
        throw PermittedMetaException.NSEE;
      }

      destination.push(source.pop());
      stackWithLastReturnedElementAtTop = destination;
      return destination.peek();
    }

    private void throwIfInvalid(IteratorFeature methodFeature) {

      }
    }

    private E transferElement(Stack<E> source, Stack<E> destination) {
      if (source.isEmpty()) {
        throw PermittedMetaException.NSEE;
      }

      destination.push(source.pop());
      stackWithLastReturnedElementAtTop = destination;
      return destination.peek();
    }

    private void throwIfInvalid(IteratorFeature methodFeature) {

   *
   * @param from the source file
   * @param to the destination file
   * @throws IOException if an I/O error occurs
   * @throws IllegalArgumentException if {@code from.equals(to)}
   */
  public static void copy(File from, File to) throws IOException {
    checkArgument(!from.equals(to), "Source %s and destination %s must be different", from, to);
    asByteSource(from).copyTo(asByteSink(to));
  }

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.Charset;

/**
 * A destination to which bytes can be written, such as a file. Unlike an {@link OutputStream}, a
 * {@code ByteSink} is not an open, stateful stream that can be written to and closed. Instead, it

  public static final byte SOH = 1;

  /**
   * Start of Text: A communication control character which precedes a sequence of characters that
   * is to be treated as an entity and entirely transmitted through to the ultimate destination.
   * Such a sequence is referred to as "text." STX may be used to terminate a sequence of characters
   * started by SOH.
   *
   * @since 8.0
   */
  public static final byte STX = 2;

  /**

 *
 * <p>For added safety, it is common for IPv6 network operators to filter all packets where either
 * the source or destination address appears to be a "compat" or "mapped" address. Filtering
 * suggestions usually recommend discarding any packets with source or destination addresses in the
 * invalid range {@code ::/3}, which includes both of these bizarre address formats. For more

   * @throws IllegalArgumentException if invalid surrogate characters are encountered
   */
  protected final String escapeSlow(String s, int index) {
    int end = s.length();

    // Get a destination buffer and setup some loop variables.
    char[] dest = Platform.charBufferFromThreadLocal();
    int destIndex = 0;
    int unescapedChunkStart = 0;

    while (index < end) {