code: public JBBPDslBuilder BitArray(final String name, final String bitLenExpression, final String sizeExpression) {
      final Item item = new Item(BinType.BIT_ARRAY, name, this.byteOrder);
      item.bitLenExpression = assertExpressionChars(bitLenExpression);
      item.sizeExpression = assertExpressionChars(sizeExpression);
      this.addItem(item);
      return this;
    }
docs: Add named bit array where each bit length is calculated through expression.
  
  @param name             name of the array, if null then anonymous one
  @param bitLenExpression expression to calculate length of the bit field, must not be null
  @param sizeExpression   expression to be used to calculate array size, must not be null
  @return the builder instance, must not be null