Depending on code in this package is bad and will cause you problems with any upgrade! But the 4.x
will be particularly painful to naughty developers that import from this package! We changed a lot
to take advantage of sweet Kotlin features.

#### Credentials.basic()

The username and password parameters to `Credentials.basic()` are now non-null strings. In OkHttp
3.x, null would yield a username or password of "null".

         * and increasing the threshold to 2^32 doesn't pay for itself, and adding another enum
         * constant hurts performance further -- I suspect because bimorphic implementation is a
         * sweet spot for the JVM.
         */
        return (a * b) % m;
      }

      @Override
      long squareMod(long a, long m) {
        return (a * a) % m;
      }
    },