$ ./date-time-bigint.plx
(2<<31)-1, raw:      1968-01-20T03:14:07Z
2<<31, raw:          1968-01-20T03:14:08Z
(2<<31)+1, raw:      1968-01-20T03:14:09Z
(2<<32)-1, raw:      2036-02-07T06:28:15Z
2<<32, raw:          2036-02-07T06:28:16Z
(2<<32)+1, raw:      2036-02-07T06:28:17Z
(2<<31)-1, str:      1968-01-20T03:14:07Z
2<<31, str:          1831-12-13T20:45:52Z
(2<<31)+1, str:      1831-12-13T20:45:53Z
(2<<31)-1, str+bi:   1968-01-20T03:14:07Z
2<<31, str+bi:       1831-12-13T20:45:52Z
(2<<31)+1, str+bi:   1831-12-13T20:45:53Z
(2<<31)-1, str+bi2:  1968-01-20T03:14:07Z
2<<31, str+bi2:      1831-12-13T20:45:52Z
(2<<31)+1, str+bi2:  1831-12-13T20:45:53Z