public static Sink sink(OutputStream out) {
    return sink(out, new Timeout());
  }
@Test public void sinkFromOutputStream() throws Exception {
    Buffer data = new Buffer();
    data.writeUtf8("a");
    data.writeUtf8(repeat('b', 9998));
    data.writeUtf8("c");

    ByteArrayOutputStream out = new ByteArrayOutputStream();
    Sink sink = Okio.sink(out);
    sink.write(data, 3);
    assertEquals("abb", out.toString("UTF-8"));
    sink.write(data, data.size());
    assertEquals("a" + repeat('b', 9998) + "c", out.toString("UTF-8"));
  }