"Mon, 05 Jan 1970 21:38:13"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700105
Only TIME
21:38:13
General datetime
1970-01-05 21:38:13Z
For Database
1970-01-05 21:38:13
For HTTP1.1
Mon, 05 Jan 1970 21:38:13 GMT