"Sun, 18 Jan 1970 00:40:21"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700118
Only TIME
00:40:21
General datetime
1970-01-18 00:40:21Z
For Database
1970-01-18 00:40:21
For HTTP1.1
Sun, 18 Jan 1970 00:40:21 GMT