"Sat, 03 Jan 1970 20:40:38"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700103
Only TIME
20:40:38
General datetime
1970-01-03 20:40:38Z
For Database
1970-01-03 20:40:38
For HTTP1.1
Sat, 03 Jan 1970 20:40:38 GMT