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