*/
  public abstract Writer openStream() throws IOException;

  /**
   * Opens a new buffered {@link Writer} for writing to this sink. The returned stream is not
   * required to be a {@link BufferedWriter} in order to allow implementations to simply delegate to
   * {@link #openStream()} when the stream returned by that method does not benefit from additional

    assertEquals("", sink.getString());
    sink.write(STRING);

    assertTrue(sink.wasStreamOpened() && sink.wasStreamClosed());
    assertEquals(STRING, sink.getString());
  }

  public void testWriteFrom_reader() throws IOException {
    StringReader reader = new StringReader(STRING);
    sink.writeFrom(reader);

    assertTrue(sink.wasStreamOpened() && sink.wasStreamClosed());

  protected ByteSink() {}

  /**
   * Returns a {@link CharSink} view of this {@code ByteSink} that writes characters to this sink as
   * bytes encoded with the given {@link Charset charset}.
   */
  public CharSink asCharSink(Charset charset) {
    return new AsCharSink(charset);
  }

  /**
   * Opens a new {@link OutputStream} for writing to this sink. This method returns a new,
   * independent stream each time it is called.

    TestCharSink sink = new TestCharSink();

    assertFalse(sink.wasStreamOpened() || sink.wasStreamClosed());

    assertEquals(STRING.length(), source.copyTo(sink));
    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());
    assertTrue(sink.wasStreamOpened() && sink.wasStreamClosed());

    assertEquals(STRING, sink.getString());
  }

    TestByteSink sink = new TestByteSink();

    assertFalse(sink.wasStreamOpened() || sink.wasStreamClosed());

    assertEquals(bytes.length, source.copyTo(sink));
    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());
    assertTrue(sink.wasStreamOpened() && sink.wasStreamClosed());

    assertArrayEquals(bytes, sink.getBytes());
  }

    TestByteSink sink = new TestByteSink();

    assertFalse(sink.wasStreamOpened() || sink.wasStreamClosed());

    assertEquals(bytes.length, source.copyTo(sink));
    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());
    assertTrue(sink.wasStreamOpened() && sink.wasStreamClosed());

    assertArrayEquals(bytes, sink.getBytes());
  }

   *
   * @param sink the output byte array
   * @param offset the offset into the array at which to start writing
   * @param value the value to write
   */
  static void store64(byte[] sink, int offset, long value) {
    // We don't want to assert in production code.
    assert offset >= 0 && offset + 8 <= sink.length;
    // Delegates to the fast (unsafe)version or the fallback.

   *
   * <ul>
   *   <li>use {@link StringReader} instead of {@link CharSequenceReader}. It is faster since it can
   *       use {@link String#getChars(int, int, char[], int)} instead of copying characters one by
   *       one with {@link CharSequence#charAt(int)}.
   *   <li>use {@link Appendable#append(CharSequence)} in {@link #copyTo(Appendable)} and {@link

   *     sink}
   */
  @CanIgnoreReturnValue
  public long copyTo(ByteSink sink) throws IOException {
    checkNotNull(sink);

    Closer closer = Closer.create();
    try {
      InputStream in = closer.register(openStream());
      OutputStream out = closer.register(sink.openStream());
      return ByteStreams.copy(in, out);
    } catch (Throwable e) {

import java.io.Reader;
import java.io.Writer;
import java.nio.CharBuffer;
import java.util.Arrays;
import java.util.logging.Logger;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * {@link SourceSinkFactory} implementations.
 *
 * @author Colin Decker
 */
public class SourceSinkFactories {

  private SourceSinkFactories() {}

  public static CharSourceFactory stringCharSourceFactory() {