code: public JBBPDslBuilder ByteArray(final String name, final String sizeExpression) {
      final Item item = new Item(BinType.BYTE_ARRAY, name, this.byteOrder);
      item.sizeExpression = assertExpressionChars(sizeExpression);
      this.addItem(item);
      return this;
    }
docs: Add named byte array which size calculated through expression.
  
  @param name           name of the array, it can be null for anonymous fields
  @param sizeExpression expression to be used to calculate array length, must not be null or empty.
  @return the builder instance, must not be null