docs: public long roundHalfEven(long instant) {
          long floor = roundFloor(instant);
          long ceiling = roundCeiling(instant);
  
          long diffFromFloor = instant - floor;
          long diffToCeiling = ceiling - instant;
  
          if (diffFromFloor < diffToCeiling) {
              // Closer to the floor - round floor
              return floor;
          } else if (diffToCeiling < diffFromFloor) {
              // Closer to the ceiling - round ceiling
              return ceiling;
          } else {
              // Round to the instant that makes this field even. If both values
              // make this field even (unlikely), favor the ceiling.
              if ((get(ceiling) & 1) == 0) {
                  return ceiling;
              }
              return floor;
          }
      }