### Question:
PingResponseDataWriter implements EntityWriter<Integer, ByteBuf> { @Override public void writeTo(Integer entity, ByteBuf target) { if (entity == null || target == null) { return; } target.writeInt(entity); }  @Override void writeTo(Integer entity, ByteBuf target);  }### Answer:
@Test public void testWritePingResponseAndParse() { ByteBuf buf = Unpooled.buffer(); PingResponseDataWriter writer = new PingResponseDataWriter(); int small = 120; writer.writeTo(small, buf); assertThat(buf.readableBytes()).isGreaterThanOrEqualTo(4); assertThat(buf.readInt()).isEqualTo(small); int big = Integer.MAX_VALUE; writer.writeTo(big, buf); assertThat(buf.readableBytes()).isGreaterThanOrEqualTo(4); assertThat(buf.readInt()).isEqualTo(big); buf.release(); }