"Sun, 18 Jan 1970 19:45:21"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700118
Only TIME
19:45:21
General datetime
1970-01-18 19:45:21Z
For Database
1970-01-18 19:45:21
For HTTP1.1
Sun, 18 Jan 1970 19:45:21 GMT