"Thu, 01 Jan 1970 21:47:20"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700101
Only TIME
21:47:20
General datetime
1970-01-01 21:47:20Z
For Database
1970-01-01 21:47:20
For HTTP1.1
Thu, 01 Jan 1970 21:47:20 GMT