to.write(buf, 0, r);
      total += r;
    }
    return total;
  }

  /**
   * Copies all bytes from the readable channel to the writable channel. Does not close or flush
   * either channel.
   *
   * @param from the readable channel to read from
   * @param to the writable channel to write to
   * @return the number of bytes copied
   * @throws IOException if an I/O error occurs
   */
  @CanIgnoreReturnValue

 *       typically implemented by opening a stream using one of the methods in the first category,
 *       doing something and finally closing the stream or channel that was opened.
 * </ul>
 *
 * @since 14.0
 * @author Colin Decker
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public abstract class ByteSink {

    try {
      RandomAccessFile raf =
          closer.register(new RandomAccessFile(file, mode == MapMode.READ_ONLY ? "r" : "rw"));
      FileChannel channel = closer.register(raf.getChannel());
      return channel.map(mode, 0, size == -1 ? channel.size() : size);
    } catch (Throwable e) {
      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**

      refreshIfEmpty();
      boolean changed = delegate.remove(o);
      if (changed) {
        totalSize--;
        removeIfEmpty();
      }
      return changed;
    }

    @Override
    public boolean removeAll(Collection<?> c) {
      if (c.isEmpty()) {
        return false;
      }
      int oldSize = size(); // calls refreshIfEmpty
      boolean changed = delegate.removeAll(c);
      if (changed) {

      }
      boolean changed = false;
      Iterator<Map<C, V>> iterator = backingMap.values().iterator();
      while (iterator.hasNext()) {
        Map<C, V> map = iterator.next();
        if (map.keySet().remove(obj)) {
          changed = true;
          if (map.isEmpty()) {
            iterator.remove();
          }
        }
      }
      return changed;
    }

    @Override

 */

package com.google.common.io;

import com.google.common.base.Charsets;
import com.google.common.testing.AbstractPackageSanityTests;
import java.lang.reflect.Method;
import java.nio.channels.FileChannel.MapMode;
import java.nio.charset.CharsetEncoder;

/**
 * Basic sanity tests for the entire package.
 *
 * @author Ben Yu
 */

public class PackageSanityTests extends AbstractPackageSanityTests {

    }
  }

  @CanIgnoreReturnValue
  @Override
  public boolean putAll(Multimap<? extends K, ? extends V> multimap) {
    boolean changed = false;
    for (Entry<? extends K, ? extends V> entry : multimap.entries()) {
      changed |= put(entry.getKey(), entry.getValue());
    }
    return changed;
  }

  @CanIgnoreReturnValue
  @Override

    }
  }

  @CanIgnoreReturnValue
  @Override
  public boolean putAll(Multimap<? extends K, ? extends V> multimap) {
    boolean changed = false;
    for (Entry<? extends K, ? extends V> entry : multimap.entries()) {
      changed |= put(entry.getKey(), entry.getValue());
    }
    return changed;
  }

  @CanIgnoreReturnValue
  @Override

          continue outer;
        }

        long newValue = oldValue + delta;
        if (atomic.compareAndSet(oldValue, newValue)) {
          return newValue;
        }
        // value changed
      }
    }
  }

  /**
   * Increments by one the value currently associated with {@code key}, and returns the old value.
   */
  @CanIgnoreReturnValue
  public long getAndIncrement(K key) {

and
https://github.com/google/guava/blob/master/CONTRIBUTING.md
before sending a pull request.

We generally welcome PRs for fixing trivial bugs or typos, but please refrain
from sending a PR with significant changes unless explicitly requested.