"Sat, 21 Feb 1970 00:52:12"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700221
Only TIME
00:52:12
General datetime
1970-02-21 00:52:12Z
For Database
1970-02-21 00:52:12
For HTTP1.1
Sat, 21 Feb 1970 00:52:12 GMT