"Sun, 18 Jan 1970 21:48:52"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700118
Only TIME
21:48:52
General datetime
1970-01-18 21:48:52Z
For Database
1970-01-18 21:48:52
For HTTP1.1
Sun, 18 Jan 1970 21:48:52 GMT