@Test
  public void testWriteTag() throws IOException {
    byte[] tags = Bytes.toBytes("---tags---");
    int tagOffset = 3;
    int length = 4;
    IndividualBytesFieldCell cell = new IndividualBytesFieldCell(Bytes.toBytes("row"), 0, 3,
      Bytes.toBytes("family"), 0, 6, Bytes.toBytes("qualifier"), 0, 9, 0L, KeyValue.Type.Put, 0,
      Bytes.toBytes("value"), 0, 5, tags, tagOffset, length);

    try (ByteArrayOutputStream output = new ByteArrayOutputStream(300)) {
      cell.write(output, true);
      byte[] buf = output.toByteArray();
      assertEquals(cell.getSerializedSize(true), buf.length);
    }
  }
Verify getXXXArray() and getXXXLength() when family/qualifier/value/tags are null. Should have
the same behaviors as {@link KeyValue}.
hbase-common/src/test/java/org/apache/hadoop/hbase/TestIndividualBytesFieldCell.java