"Sat, 03 Jan 1970 21:38:40"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700103
Only TIME
21:38:40
General datetime
1970-01-03 21:38:40Z
For Database
1970-01-03 21:38:40
For HTTP1.1
Sat, 03 Jan 1970 21:38:40 GMT