"Tue, 20 Jan 1970 18:15:50"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700120
Only TIME
18:15:50
General datetime
1970-01-20 18:15:50Z
For Database
1970-01-20 18:15:50
For HTTP1.1
Tue, 20 Jan 1970 18:15:50 GMT