"Fri, 20 Feb 1970 00:52:21"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700220
Only TIME
00:52:21
General datetime
1970-02-20 00:52:21Z
For Database
1970-02-20 00:52:21
For HTTP1.1
Fri, 20 Feb 1970 00:52:21 GMT