default boolean ifBigInteger(Consumer<BigInteger> consumer){
  if (isBigInteger()) {
    consumer.accept(asBigInteger());
    return true;
  }
  return false;
}

default boolean ifBigInteger ( Consumer < BigInteger > consumer ) { if ( isBigInteger ( ) ) { consumer . accept ( asBigInteger ( ) ) ; return true ; } return false ; }
if a value is a variable - sized integer , invoke the specified consumer with the value , otherwise do nothing .
