"Tue, 20 Jan 1970 21:48:40"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700120
Only TIME
21:48:40
General datetime
1970-01-20 21:48:40Z
For Database
1970-01-20 21:48:40
For HTTP1.1
Tue, 20 Jan 1970 21:48:40 GMT