"Sun, 18 Jan 1970 20:42:44"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700118
Only TIME
20:42:44
General datetime
1970-01-18 20:42:44Z
For Database
1970-01-18 20:42:44
For HTTP1.1
Sun, 18 Jan 1970 20:42:44 GMT