code: protected long calculatePowerOfTwo(long attempt) {
          long step;
          if (attempt >= 64) { //safeguard against overflow in the bitshift operation
              step = Long.MAX_VALUE;
          } else {
              step = (1L << (attempt - 1));
          }
          //round will cap at Long.MAX_VALUE
          return Math.round(step * growBy);
      }
docs: fastpath with bitwise operator