"Sat, 21 Feb 1970 19:40:50"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700221
Only TIME
19:40:50
General datetime
1970-02-21 19:40:50Z
For Database
1970-02-21 19:40:50
For HTTP1.1
Sat, 21 Feb 1970 19:40:50 GMT