"Sun, 04 Jan 1970 21:40:00"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700104
Only TIME
21:40:00
General datetime
1970-01-04 21:40:00Z
For Database
1970-01-04 21:40:00
For HTTP1.1
Sun, 04 Jan 1970 21:40:00 GMT