@SuppressWarnings("ShortCircuitBoolean")
  public static long saturatedAdd(long a, long b) {
    long naiveSum = a + b;
    if ((a ^ b) < 0 | (a ^ naiveSum) >= 0) {
      // If a and b have different signs or a has the same sign as the result then there was no
      // overflow, return.
      return naiveSum;
    }
    // we did over/under flow, if the sign is negative we should return MAX otherwise MIN
    return Long.MAX_VALUE + ((naiveSum >>> (Long.SIZE - 1)) ^ 1);
  }
Returns the sum of {@code a} and {@code b} unless it would overflow or underflow in which case
{@code Long.MAX_VALUE} or {@code Long.MIN_VALUE} is returned, respectively.
src/main/java/com/google/maps/internal/ratelimiter/LongMath.java