"Thu, 01 Jan 1970 20:39:40"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700101
Only TIME
20:39:40
General datetime
1970-01-01 20:39:40Z
For Database
1970-01-01 20:39:40
For HTTP1.1
Thu, 01 Jan 1970 20:39:40 GMT