"Wed, 21 Jan 1970 21:48:37"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700121
Only TIME
21:48:37
General datetime
1970-01-21 21:48:37Z
For Database
1970-01-21 21:48:37
For HTTP1.1
Wed, 21 Jan 1970 21:48:37 GMT