docs: private static long remainder(long dividend, long divisor)
      {
          if (divisor < 0)
          { // i.e., divisor >= 2^63:
              if (compareUnsigned(dividend, divisor) < 0)
              {
                  return dividend; // dividend < divisor
              }
              else
              {
                  return dividend - divisor; // dividend >= divisor
              }
          }
  
          // Optimization - use signed modulus if dividend < 2^63
          if (dividend >= 0)
          {
              return dividend % divisor;
          }
  
          /*
           * Otherwise, approximate the quotient, check, and correct if necessary. Our approximation is guaranteed to be
           * either exact or one less than the correct value. This follows from fact that floor(floor(x)/i) == floor(x/i)
           * for any real x and integer i != 0. The proof is not quite trivial.
           */
          long quotient = ((dividend >>> 1) / divisor) << 1;
          long rem = dividend - quotient * divisor;
          return rem - (compareUnsigned(rem, divisor) >= 0 ? divisor : 0);
      }