private byte[] byteVars() {
    if (byteVars.length == size) {
      byte[] newVars = new byte[size << 1];
      System.arraycopy(byteVars, 0, newVars, 0, size);
      return byteVars = newVars;
    }
    return byteVars;
  }
Get a subset of this ColumnBuffer, starting from the 1st value.

@param end index after the last value to include
serde/src/java/org/apache/hadoop/hive/serde2/thrift/ColumnBuffer.java