This is a quick and dirty project to illustrate a bug where Golang time.After fails to wake the process for large delays.
3h0m0s 2016-10-20 10:59:04.233645865 +0100 BST: should wake at 2016-10-20 13:59:04.233645865 +0100 BST in 3h0m0s
9h0m0s 2016-10-20 10:59:04.350703594 +0100 BST: should wake at 2016-10-20 19:59:04.350703594 +0100 BST in 9h0m0s
10m0s 2016-10-20 10:59:04.350711442 +0100 BST: should wake at 2016-10-20 11:09:04.350711442 +0100 BST in 10m0s
8h0m0s 2016-10-20 10:59:04.365249689 +0100 BST: should wake at 2016-10-20 18:59:04.365249689 +0100 BST in 8h0m0s
1h0m0s 2016-10-20 10:59:04.385879887 +0100 BST: should wake at 2016-10-20 11:59:04.385879887 +0100 BST in 1h0m0s
7h0m0s 2016-10-20 10:59:04.389250374 +0100 BST: should wake at 2016-10-20 17:59:04.389250374 +0100 BST in 7h0m0s
2h0m0s 2016-10-20 10:59:04.402031663 +0100 BST: should wake at 2016-10-20 12:59:04.402031663 +0100 BST in 2h0m0s
5h0m0s 2016-10-20 10:59:04.411631508 +0100 BST: should wake at 2016-10-20 15:59:04.411631508 +0100 BST in 5h0m0s
4h0m0s 2016-10-20 10:59:04.44162023 +0100 BST: should wake at 2016-10-20 14:59:04.44162023 +0100 BST in 4h0m0s
10s 2016-10-20 10:59:04.442757967 +0100 BST: should wake at 2016-10-20 10:59:14.442757967 +0100 BST in 10s
6h0m0s 2016-10-20 10:59:04.446185807 +0100 BST: should wake at 2016-10-20 16:59:04.446185807 +0100 BST in 6h0m0s
10s 2016-10-20 10:59:14.442956722 +0100 BST: did wake with delta 198.755µs
real 0m10.850s
user 0m0.169s
sys 0m0.099s
10m0s 2016-10-20 11:09:04.351541782 +0100 BST: did wake with delta 830.34µs
real 10m0.759s
user 0m0.165s
sys 0m0.090s
1h0m0s 2016-10-20 11:59:04.389439653 +0100 BST: did wake with delta 3.559766ms
real 60m0.799s
user 0m0.198s
sys 0m0.093s
2h0m0s 2016-10-20 12:59:04.406737243 +0100 BST: did wake with delta 4.70558ms
real 120m0.816s
user 0m0.240s
sys 0m0.111s
3h0m0s 2016-10-20 13:59:04.235482729 +0100 BST: did wake with delta 1.836864ms
real 180m0.644s
user 0m0.300s
sys 0m0.130s
4h0m0s 2016-10-20 14:59:04.443901762 +0100 BST: did wake with delta 2.281532ms
real 240m0.854s
user 0m0.322s
sys 0m0.119s
5h0m0s 2016-10-20 15:59:04.415292046 +0100 BST: did wake with delta 3.660538ms
real 300m0.823s
user 0m0.360s
sys 0m0.127s
6h0m0s 2016-10-20 17:26:37.232606209 +0100 BST: did wake with delta 27m32.786420402s
real 387m33.638s
user 0m0.436s
sys 0m0.149s
7h0m0s 2016-10-20 18:26:37.106103255 +0100 BST: did wake with delta 27m32.716852881s
real 447m33.502s
user 0m0.439s
sys 0m0.144s
9h0m0s 2016-10-21 09:37:21.668181946 +0100 BST: did wake with delta 13h38m17.317478352s
8h0m0s 2016-10-21 09:37:21.668608365 +0100 BST: did wake with delta 14h38m17.303358676s
real 1358m18.063s
user 0m0.459s
sys 0m0.142s
real 1358m18.049s
user 0m0.469s
sys 0m0.148s
Possibly caused by app nap? Resizing the terminal window (which I believe results in signals being sent) unfroze the 8h and 9h delays which failed to fire overnight (see above).